UNCLASSIFIED

VMware vSphere 6.5 ESXi Security Technical Implementation Guide

Version 1 Release 4

24 Apr 2020

Table of Contents

Introduction

Executive Summary

The VMware vSphere 6.5 ESXi Security Technical Implementation Guide is published as a tool to improve the security of the Department of Defense (DoD) information systems.

Authority

DoD Instruction (DoDI) 8500.01 requires that “all IT that receives, processes, stores, displays, or transmits DoD information will be […] configured […] consistent with applicable DoD cybersecurity policies, standards, and architectures” and tasks that Defense Information Systems Agency (DISA) “develops and maintains control correlation identifiers (CCIs), security requirements guides (SRGs), security technical implementation guides (STIGs), and mobile code risk categories and usage guides that implement and are consistent with DoD cybersecurity policies, standards, architectures, security controls, and validation procedures, with the support of the NSA/CSS, using input from stakeholders, and using automation whenever possible.” This document is provided under the authority of DoDI 8500.01.

Although the use of the principles and guidelines in these SRGs/STIGs provides an environment that contributes to the security requirements of DoD systems, applicable NIST SP 800-53 cybersecurity controls need to be applied to all systems and architectures based on the Committee on National Security Systems (CNSS) Instruction (CNSSI) 1253.

Vulnerability Severity Category Code Definitions

Severity Category Codes (referred to as CAT) are a measure of vulnerabilities used to assess a facility or system security posture. Each security policy specified in this document is assigned a Severity Code of CAT I, II, or III.

Category Code Guidelines
CAT I Any vulnerability, the exploitation of which will, directly and immediately result in loss of Confidentiality, Availability, or Integrity.
CAT II Any vulnerability, the exploitation of which has a potential to result in loss of Confidentiality, Availability, or Integrity.
CAT III Any vulnerability, the existence of which degrades measures to protect against loss of Confidentiality, Availability, or Integrity.

STIG Distribution

Parties within the DoD and Federal Government’s computing environments can obtain the applicable STIG from the Cyber Exchange website at https://cyber.mil/. This site contains the latest copies of STIGs, SRGs, and other related security information. Those without a Common Access Card (CAC) that has DoD Certificates can obtain the STIG from https://public.cyber.mil/.

SRG Compliance Reporting

All technical NIST SP 800-53 requirements were considered while developing this STIG. Requirements that are applicable and configurable will be included in the final STIG. A report marked For Official Use Only (FOUO) will be available for those items that did not meet requirements. This report will be available to component Authorizing Official (AO) personnel for risk assessment purposes by request via email to: disa.stig_spt@mail.mil.

Document Revision Process

Comments or proposed revisions to this document should be sent via email to the following address: disa.stig_spt@mail.mil. DISA will coordinate all change requests with the relevant DoD organizations before inclusion in this document. Approved changes will be made in accordance with the DISA maintenance release schedule.

Other Considerations

DISA accepts no liability for the consequences of applying specific configuration settings made on the basis of the SRGs/STIGs. It must be noted that the configuration settings specified should be evaluated in a local, representative test environment before implementation in a production environment, especially within large user populations. The extensive variety of environments makes it impossible to test these configuration settings for all potential software configurations.

For some production environments, failure to test before implementation may lead to a loss of required functionality. Evaluating the risks and benefits to a system’s particular circumstances and requirements is the system owner’s responsibility. The evaluated risks resulting from not applying specified configuration settings must be approved by the responsible Authorizing Official. Furthermore, DISA implies no warranty that the application of all specified configurations will make a system 100 percent secure.

Security guidance is provided for the Department of Defense. While other agencies and organizations are free to use it, care must be given to ensure that all applicable security guidance is applied both at the device hardening level as well as the architectural level due to the fact that some of the settings may not be able to be configured in environments outside the DoD architecture.

Product Approval Disclaimer

The existence of a STIG does not equate to DoD approval for the procurement or use of a product.

STIGs provide configurable operational security guidance for products being used by the DoD. STIGs, along with vendor confidential documentation, also provide a basis for assessing compliance with Cybersecurity controls/control enhancements, which supports system Assessment and Authorization (A&A) under the DoD Risk Management Framework (RMF). DoD Authorizing Officials (AOs) may request available vendor confidential documentation for a product that has a STIG for product evaluation and RMF purposes from disa.stig_spt@mail.mil. This documentation is not published for general access to protect the vendor’s proprietary information.

AOs have the purview to determine product use/approval IAW DoD policy and through RMF risk acceptance. Inputs into acquisition or pre-acquisition product selection include such processes as:

Requirements Catalog

Table of Requirements
STIG ID Group ID Rule ID Requirement Severity
ESXI-65-000001 V-93949 SV-104035r1_rule The ESXi host must limit the number of concurrent sessions to ten for all accounts and/or account types by enabling lockdown mode. CAT II
ESXI-65-000002 V-93951 SV-104037r1_rule The ESXi host must verify the DCUI.Access list. CAT III
ESXI-65-000003 V-93953 SV-104039r1_rule The ESXi host must verify the exception users list for lockdown mode. CAT III
ESXI-65-000004 V-93955 SV-104041r1_rule Remote logging for ESXi hosts must be configured. CAT II
ESXI-65-000005 V-93957 SV-104043r1_rule The ESXi host must enforce the limit of three consecutive invalid logon attempts by a user. CAT II
ESXI-65-000006 V-93959 SV-104045r1_rule The ESXi host must enforce the unlock timeout of 15 minutes after a user account is locked out. CAT II
ESXI-65-000007 V-93961 SV-104047r1_rule The ESXi host must display the Standard Mandatory DoD Notice and Consent Banner before granting access to the system. CAT II
ESXI-65-000008 V-93963 SV-104049r1_rule The ESXi host must display the Standard Mandatory DoD Notice and Consent Banner before granting access to the system. CAT II
ESXI-65-000009 V-93965 SV-104051r1_rule The ESXi host SSH daemon must be configured with the Department of Defense (DoD) login banner. CAT II
ESXI-65-000010 V-93967 SV-104053r1_rule The ESXi host SSH daemon must use DoD-approved encryption to protect the confidentiality of remote access sessions. CAT II
ESXI-65-000011 V-93969 SV-104055r1_rule The ESXi host SSH daemon must be configured to use only the SSHv2 protocol. CAT I
ESXI-65-000012 V-93971 SV-104057r1_rule The ESXi host SSH daemon must ignore .rhosts files. CAT II
ESXI-65-000013 V-93973 SV-104059r1_rule The ESXi host SSH daemon must not allow host-based authentication. CAT II
ESXI-65-000014 V-93975 SV-104061r1_rule The ESXi host SSH daemon must not permit root logins. CAT III
ESXI-65-000015 V-93977 SV-104063r1_rule The ESXi host SSH daemon must not allow authentication using an empty password. CAT I
ESXI-65-000016 V-93979 SV-104065r1_rule The ESXi host SSH daemon must not permit user environment settings. CAT II
ESXI-65-000017 V-93981 SV-104067r1_rule The ESXi host SSH daemon must be configured to only use Message Authentication Codes (MACs) employing FIPS 140-2 approved cryptographic hash algorithms. CAT II
ESXI-65-000018 V-93983 SV-104069r1_rule The ESXi host SSH daemon must not permit GSSAPI authentication. CAT III
ESXI-65-000019 V-93985 SV-104071r1_rule The ESXi host SSH daemon must not permit Kerberos authentication. CAT III
ESXI-65-000020 V-93987 SV-104073r1_rule The ESXi host SSH daemon must perform strict mode checking of home directory configuration files. CAT II
ESXI-65-000021 V-93989 SV-104075r1_rule The ESXi host SSH daemon must not allow compression or must only allow compression after successful authentication. CAT II
ESXI-65-000022 V-93991 SV-104077r1_rule The ESXi host SSH daemon must be configured to not allow gateway ports. CAT III
ESXI-65-000023 V-93993 SV-104079r1_rule The ESXi host SSH daemon must be configured to not allow X11 forwarding. CAT II
ESXI-65-000024 V-93995 SV-104081r1_rule The ESXi host SSH daemon must not accept environment variables from the client. CAT II
ESXI-65-000025 V-93997 SV-104083r1_rule The ESXi host SSH daemon must not permit tunnels. CAT II
ESXI-65-000026 V-93999 SV-104085r1_rule The ESXi host SSH daemon must set a timeout count on idle sessions. CAT III
ESXI-65-000027 V-94001 SV-104087r1_rule The ESXi hostSSH daemon must set a timeout interval on idle sessions. CAT III
ESXI-65-000028 V-94003 SV-104089r1_rule The ESXi host SSH daemon must limit connections to a single session. CAT II
ESXI-65-000029 V-94005 SV-104091r1_rule The ESXi host must remove keys from the SSH authorized_keys file. CAT II
ESXI-65-000030 V-94007 SV-104093r1_rule The ESXi host must produce audit records containing information to establish what type of events occurred. CAT III
ESXI-65-000031 V-94009 SV-104095r1_rule The ESXi host must enforce password complexity by requiring that at least one upper-case character be used. CAT II
ESXI-65-000032 V-94011 SV-104097r1_rule The ESXi host must prohibit the reuse of passwords within five iterations. CAT II
ESXI-65-000033 V-94013 SV-104099r1_rule The password hashes stored on the ESXi host must have been generated using a FIPS 140-2 approved cryptographic hashing algorithm. CAT II
ESXI-65-000034 V-94015 SV-104101r1_rule The ESXi host must disable the Managed Object Browser (MOB). CAT II
ESXI-65-000035 V-94017 SV-104103r1_rule The ESXi host must be configured to disable non-essential capabilities by disabling SSH. CAT II
ESXI-65-000036 V-94019 SV-104105r1_rule The ESXi host must disable ESXi Shell unless needed for diagnostics or troubleshooting. CAT II
ESXI-65-000037 V-94021 SV-104107r1_rule The ESXi host must use Active Directory for local user authentication. CAT III
ESXI-65-000038 V-94023 SV-104109r2_rule The ESXi host must use the vSphere Authentication Proxy to protect passwords when adding ESXi hosts to Active Directory. CAT II
ESXI-65-000039 V-94025 SV-104111r1_rule Active Directory ESX Admin group membership must not be used when adding ESXi hosts to Active Directory. CAT III
ESXI-65-000040 V-94027 SV-104113r1_rule The ESXi host must use multifactor authentication for local access to privileged accounts. CAT III
ESXI-65-000041 V-94029 SV-104115r1_rule The ESXi host must set a timeout to automatically disable idle sessions after 10 minutes. CAT II
ESXI-65-000042 V-94031 SV-104117r1_rule The ESXi host must terminate shell services after 10 minutes. CAT II
ESXI-65-000043 V-94033 SV-104119r1_rule The ESXi host must logout of the console UI after 10 minutes. CAT II
ESXI-65-000044 V-94035 SV-104121r1_rule The ESXi host must enable kernel core dumps. CAT III
ESXI-65-000045 V-94037 SV-104123r1_rule The ESXi host must enable a persistent log location for all locally stored logs. CAT II
ESXI-65-000046 V-94039 SV-104125r1_rule The ESXi host must configure NTP time synchronization. CAT II
ESXI-65-000047 V-94041 SV-104127r1_rule The ESXi Image Profile and VIB Acceptance Levels must be verified. CAT I
ESXI-65-000048 V-94043 SV-104129r1_rule The ESXi host must protect the confidentiality and integrity of transmitted information by isolating vMotion traffic. CAT II
ESXI-65-000049 V-100543 SV-109647r1_rule The ESXi host must protect the confidentiality and integrity of transmitted information by protecting ESXi management traffic. CAT II
ESXI-65-000050 V-94047 SV-104133r1_rule The ESXi host must protect the confidentiality and integrity of transmitted information by protecting IP based management traffic. CAT II
ESXI-65-000052 V-94051 SV-104137r1_rule The ESXi host must protect the confidentiality and integrity of transmitted information by utilizing different TCP/IP stacks where possible. CAT III
ESXI-65-000053 V-94053 SV-104139r1_rule SNMP must be configured properly on the ESXi host. CAT II
ESXI-65-000054 V-94055 SV-104141r1_rule The ESXi host must enable bidirectional CHAP authentication for iSCSI traffic. CAT III
ESXI-65-000055 V-94057 SV-104143r1_rule The ESXi host must disable Inter-VM transparent page sharing. CAT III
ESXI-65-000056 V-94059 SV-104145r1_rule The ESXi host must configure the firewall to restrict access to services running on the host. CAT II
ESXI-65-000057 V-94061 SV-104147r1_rule The ESXi host must configure the firewall to block network traffic by default. CAT II
ESXI-65-000058 V-94063 SV-104149r1_rule The ESXi host must enable BPDU filter on the host to prevent being locked out of physical switch ports with Portfast and BPDU Guard enabled. CAT III
ESXI-65-000059 V-94065 SV-104151r1_rule The virtual switch Forged Transmits policy must be set to reject on the ESXi host. CAT II
ESXI-65-000060 V-94067 SV-104153r1_rule The virtual switch MAC Address Change policy must be set to reject on the ESXi host. CAT I
ESXI-65-000061 V-94069 SV-104155r1_rule The virtual switch Promiscuous Mode policy must be set to reject on the ESXi host. CAT II
ESXI-65-000062 V-94071 SV-104157r1_rule The ESXi host must prevent unintended use of the dvFilter network APIs. CAT II
ESXI-65-000063 V-94073 SV-104159r1_rule For the ESXi host all port groups must be configured to a value other than that of the native VLAN. CAT II
ESXI-65-000064 V-94075 SV-104161r1_rule For the ESXi host all port groups must not be configured to VLAN 4095 unless Virtual Guest Tagging (VGT) is required. CAT II
ESXI-65-000065 V-94077 SV-104163r1_rule For the ESXi host all port groups must not be configured to VLAN values reserved by upstream physical switches. CAT II
ESXI-65-000066 V-94079 SV-104165r1_rule For physical switch ports connected to the ESXi host, the non-negotiate option must be configured for trunk links between external physical switches and virtual switches in VST mode. CAT II
ESXI-65-000067 V-94081 SV-104167r1_rule All ESXi host-connected physical switch ports must be configured with spanning tree disabled. CAT III
ESXI-65-000068 V-94083 SV-104169r1_rule All ESXi host-connected virtual switch VLANs must be fully documented and have only the required VLANs. CAT II
ESXI-65-000070 V-94349 SV-104303r2_rule The ESXi host must not provide root/administrator level access to CIM-based hardware monitoring tools or other third-party applications. CAT II
ESXI-65-000071 V-94477 SV-104307r1_rule The ESXi host must verify the integrity of the installation media before installing ESXi. CAT I
ESXI-65-000072 V-94479 SV-104309r1_rule The ESXi host must have all security patches and updates installed. CAT I
ESXI-65-000076 V-94487 SV-104317r1_rule The ESXi host must enable Secure Boot. CAT II
ESXI-65-000078 V-94489 SV-104319r1_rule The ESXi host must use DoD-approved certificates. CAT II
ESXI-65-100037 V-94505 SV-104335r2_rule The ESXi host must require individuals to be authenticated with an individual authenticator prior to using a group authenticator by using Active Directory for local user authentication. CAT III

Requirement Details
STIG ID:
ESXI-65-000001		 Group ID:
V-93949		 Rule ID:
SV-104035r1_rule		 Severity:
CAT II
Requirement: The ESXi host must limit the number of concurrent sessions to ten for all accounts and/or account types by enabling lockdown mode.
Discussion: Enabling lockdown mode disables direct access to an ESXi host requiring the host be managed remotely from vCenter Server. This is done to ensure the roles and access controls implemented in vCenter are always enforced and users cannot bypass them by logging into a host directly. By forcing all interaction to occur through vCenter Server, the risk of someone inadvertently attaining elevated privileges or performing tasks that are not properly audited is greatly reduced.
Check: From the vSphere Web Client select the ESXi Host and go to Configure >> System >> Security Profile. Scroll down to "Lockdown Mode" and verify it is set to Enabled (Normal or Strict).

or

From a PowerCLI command prompt while connected to the ESXi host run the following command:

Get-VMHost | Select Name,@{N="Lockdown";E={$_.Extensiondata.Config.LockdownMode}}

If Lockdown Mode is disabled, this is a finding.

For environments that do not use vCenter server to manage ESXi, this is not applicable.
Fix: From the vSphere Web Client select the ESXi Host and go to Configure >> System >> Security Profile. Click edit on "Lockdown Mode" and set to Enabled (Normal or Strict).

or

From a PowerCLI command prompt while connected to the ESXi host run the following commands:

$level = "lockdownNormal" OR "lockdownStrict"
$vmhost = Get-VMHost -Name <hostname> | Get-View
$lockdown = Get-View $vmhost.ConfigManager.HostAccessManager
$lockdown.ChangeLockdownMode($level)

Note: In strict lockdown mode the DCUI service is stopped. If the connection to vCenter Server is lost and the vSphere Web Client is no longer available, the ESXi host becomes inaccessible.
References:
  • CCI-000054

STIG ID:
ESXI-65-000002		 Group ID:
V-93951		 Rule ID:
SV-104037r1_rule		 Severity:
CAT III
Requirement: The ESXi host must verify the DCUI.Access list.
Discussion: Lockdown mode disables direct host access requiring that admins manage hosts from vCenter Server. However, if a host becomes isolated from vCenter Server, the admin is locked out and can no longer manage the host. If you are using normal lockdown mode, you can avoid becoming locked out of an ESXi host that is running in lockdown mode, by setting DCUI.Access to a list of highly trusted users who can override lockdown mode and access the DCUI. The DCUI is not running in strict lockdown mode.
Check: From the vSphere Web Client select the ESXi Host and go to Configure >> System >> Advanced System Settings. Select the DCUI.Access value and verify only the root user is listed.

or

From a PowerCLI command prompt while connected to the ESXi host run the following command:

Get-VMHost | Get-AdvancedSetting -Name DCUI.Access and verify it is set to root.

If the DCUI.Access is not restricted to root, this is a finding.

Note: This list is only for local user accounts and should only contain the root user.

For environments that do not use vCenter server to manage ESXi, this is not applicable.
Fix: From the vSphere Web Client select the ESXi Host and go to Configure >> System >> Advanced System Settings. Click Edit and select the DCUI.Access value and configure it to root.

or

From a PowerCLI command prompt while connected to the ESXi host run the following command:

Get-VMHost | Get-AdvancedSetting -Name DCUI.Access | Set-AdvancedSetting -Value "root"
References:
  • CCI-000366

STIG ID:
ESXI-65-000003		 Group ID:
V-93953		 Rule ID:
SV-104039r1_rule		 Severity:
CAT III
Requirement: The ESXi host must verify the exception users list for lockdown mode.
Discussion: In vSphere you can add users to the Exception Users list from the vSphere Web Client. These users do not lose their permissions when the host enters lockdown mode. Usually you may want to add service accounts such as a backup agent to the Exception Users list. Verify that the list of users who are exempted from losing permissions is legitimate and as needed per your environment. Users who do not require special permissions should not be exempted from lockdown mode.
Check: From the vSphere Web Client select the ESXi Host and go to Configure >> System >> Security Profile. Under lockdown mode review the exception users list.

or

From a PowerCLI command prompt while connected to the ESXi host run the following script:

$vmhost = Get-VMHost | Get-View
$lockdown = Get-View $vmhost.ConfigManager.HostAccessManager
$lockdown.QueryLockdownExceptions()

If the Exception users list contains accounts that do not require special permissions, this is a finding.

Note - This list is not intended for system administrator accounts but for special circumstances such as a service account.

For environments that do not use vCenter server to manage ESXi, this is not applicable.
Fix: From the vSphere Web Client select the ESXi Host and go to Configure >> System >> Security Profile. Under lockdown mode click Edit and remove unnecessary users to the exceptions list.
References:
  • CCI-000366

STIG ID:
ESXI-65-000004		 Group ID:
V-93955		 Rule ID:
SV-104041r1_rule		 Severity:
CAT II
Requirement: Remote logging for ESXi hosts must be configured.
Discussion: Remote logging to a central log host provides a secure, centralized store for ESXi logs. By gathering host log files onto a central host it can more easily monitor all hosts with a single tool. It can also do aggregate analysis and searching to look for such things as coordinated attacks on multiple hosts. Logging to a secure, centralized log server also helps prevent log tampering and also provides a long-term audit record.
Check: From the vSphere Web Client select the ESXi Host and go to Configure >> System >> Advanced System Settings. Select the Syslog.global.logHost value and verify it is set to a site specific syslog server hostname.

or

From a PowerCLI command prompt while connected to the ESXi host run the following command:

Get-VMHost | Get-AdvancedSetting -Name Syslog.global.logHost

If the Syslog.global.logHost setting is not set to a site specific syslog server, this is a finding.
Fix: From the vSphere Web Client select the ESXi Host and go to Configure >> System >> Advanced System Settings. Click Edit and select the Syslog.global.logHost value and configure it to a site specific syslog server.

or

From a PowerCLI command prompt while connected to the ESXi host run the following commands:

Get-VMHost | Get-AdvancedSetting -Name Syslog.global.logHost | Set-AdvancedSetting -Value "<syslog server hostname>"
References:
  • CCI-000067

STIG ID:
ESXI-65-000005		 Group ID:
V-93957		 Rule ID:
SV-104043r1_rule		 Severity:
CAT II
Requirement: The ESXi host must enforce the limit of three consecutive invalid logon attempts by a user.
Discussion: By limiting the number of failed login attempts, the risk of unauthorized access via user password guessing, otherwise known as brute-forcing, is reduced. Limits are imposed by locking the account.
Check: From the vSphere Web Client select the ESXi Host and go to Configure >> System >> Advanced System Settings. Select the Security.AccountLockFailures value and verify it is set to 3.

or

From a PowerCLI command prompt while connected to the ESXi host run the following command:

Get-VMHost | Get-AdvancedSetting -Name Security.AccountLockFailures and verify it is set to 3.

If the Security.AccountLockFailures is set to a value other than 3, this is a finding.
Fix: From the vSphere Web Client select the ESXi Host and go to Configure >> System >> Advanced System Settings. Click Edit and select the Security.AccountLockFailures value and configure it to 3.

or

From a PowerCLI command prompt while connected to the ESXi host run the following command:

Get-VMHost | Get-AdvancedSetting -Name Security.AccountLockFailures | Set-AdvancedSetting -Value 3
References:
  • CCI-000044

STIG ID:
ESXI-65-000006		 Group ID:
V-93959		 Rule ID:
SV-104045r1_rule		 Severity:
CAT II
Requirement: The ESXi host must enforce the unlock timeout of 15 minutes after a user account is locked out.
Discussion: By limiting the number of failed login attempts, the risk of unauthorized access via user password guessing, otherwise known as brute-forcing, is reduced. Limits are imposed by locking the account.
Check: From the vSphere Web Client select the ESXi Host and go to Configure >> System >> Advanced System Settings. Select the Security.AccountUnlockTime value and verify it is set to 900.

or

From a PowerCLI command prompt while connected to the ESXi host run the following command:

Get-VMHost | Get-AdvancedSetting -Name Security.AccountUnlockTime and verify it is set to 900.

If the Security.AccountUnlockTime is set to a value other than 900, this is a finding.
Fix: From the vSphere Web Client select the ESXi Host and go to Configure >> System >> Advanced System Settings. Click Edit and select the Security.AccountUnlockTime value and configure it to 900.

or

From a PowerCLI command prompt while connected to the ESXi host run the following commands:

Get-VMHost | Get-AdvancedSetting -Name Security.AccountUnlockTime | Set-AdvancedSetting -Value 900
References:
  • CCI-002238

STIG ID:
ESXI-65-000007		 Group ID:
V-93961		 Rule ID:
SV-104047r1_rule		 Severity:
CAT II
Requirement: The ESXi host must display the Standard Mandatory DoD Notice and Consent Banner before granting access to the system.
Discussion: Failure to display the DoD logon banner prior to a log in attempt will negate legal proceedings resulting from unauthorized access to system resources.
Check: From the vSphere Web Client select the ESXi Host and go to Configure >> System >> Advanced System Settings. Select the Annotations.WelcomeMessage value and verify it contains the DoD logon banner to follow.

or

From a PowerCLI command prompt while connected to the ESXi host run the following command:

Get-VMHost | Get-AdvancedSetting -Name Annotations.WelcomeMessage

Check for either of the following login banners based on the character limitations imposed by the system. An exact match of the text is required. If one of these banners is not displayed, this is a finding.

You are accessing a U.S. Government (USG) Information System (IS) that is provided for USG-authorized use only.

By using this IS (which includes any device attached to this IS), you consent to the following conditions:

-The USG routinely intercepts and monitors communications on this IS for purposes including, but not limited to, penetration testing, COMSEC monitoring, network operations and defense, personnel misconduct (PM), law enforcement (LE), and counterintelligence (CI) investigations.

-At any time, the USG may inspect and seize data stored on this IS.

-Communications using, or data stored on, this IS are not private, are subject to routine monitoring, interception, and search, and may be disclosed or used for any USG-authorized purpose.

-This IS includes security measures (e.g., authentication and access controls) to protect USG interests- -not for your personal benefit or privacy.

-Notwithstanding the above, using this IS does not constitute consent to PM, LE or CI investigative searching or monitoring of the content of privileged communications, or work product, related to personal representation or services by attorneys, psychotherapists, or clergy, and their assistants. Such communications and work product are private and confidential. See User Agreement for details.

OR

I've read & consent to terms in IS user agreem't.

If the DCUI logon screen does not display the DoD logon banner, this is a finding.
Fix: From a PowerCLI command prompt while connected to the ESXi host copy the following contents into a script(.ps1 file) and run to set the DCUI screen to display the DoD logon banner:

<script begin>

$value = @"
{bgcolor:black} {/color}{align:left}{bgcolor:black}{color:yellow}{hostname} , {ip}{/color}{/bgcolor}{/align}
{bgcolor:black} {/color}{align:left}{bgcolor:black}{color:yellow}{esxproduct} {esxversion}{/color}{/bgcolor}{/align}
{bgcolor:black} {/color}{align:left}{bgcolor:black}{color:yellow}{memory} RAM{/color}{/bgcolor}{/align}
{bgcolor:black} {/color}{align:left}{bgcolor:black}{color:white} {/color}{/bgcolor}{/align}
{bgcolor:black} {/color}{align:left}{bgcolor:yellow}{color:black} {/color}{/bgcolor}{/align}
{bgcolor:black} {/color}{align:left}{bgcolor:yellow}{color:black} You are accessing a U.S. Government (USG) Information System (IS) that is provided for USG-authorized use only. By {/color}{/bgcolor}{/align}
{bgcolor:black} {/color}{align:left}{bgcolor:yellow}{color:black} using this IS (which includes any device attached to this IS), you consent to the following conditions: {/color}{/bgcolor}{/align}
{bgcolor:black} {/color}{align:left}{bgcolor:yellow}{color:black} {/color}{/bgcolor}{/align}
{bgcolor:black} {/color}{align:left}{bgcolor:yellow}{color:black} - The USG routinely intercepts and monitors communications on this IS for purposes including, but not limited {/color}{/bgcolor}{/align}
{bgcolor:black} {/color}{align:left}{bgcolor:yellow}{color:black} to, penetration testing, COMSEC monitoring, network operations and defense, personnel misconduct (PM), law {/color}{/bgcolor}{/align}
{bgcolor:black} {/color}{align:left}{bgcolor:yellow}{color:black} enforcement (LE), and counterintelligence (CI) investigations. {/color}{/bgcolor}{/align}
{bgcolor:black} {/color}{align:left}{bgcolor:yellow}{color:black} {/color}{/bgcolor}{/align}
{bgcolor:black} {/color}{align:left}{bgcolor:yellow}{color:black} - At any time, the USG may inspect and seize data stored on this IS. {/color}{/bgcolor}{/align}
{bgcolor:black} {/color}{align:left}{bgcolor:yellow}{color:black} {/color}{/bgcolor}{/align}
{bgcolor:black} {/color}{align:left}{bgcolor:yellow}{color:black} - Communications using, or data stored on, this IS are not private, are subject to routine monitoring, {/color}{/bgcolor}{/align}
{bgcolor:black} {/color}{align:left}{bgcolor:yellow}{color:black} interception, and search, and may be disclosed or used for any USG-authorized purpose. {/color}{/bgcolor}{/align}
{bgcolor:black} {/color}{align:left}{bgcolor:yellow}{color:black} {/color}{/bgcolor}{/align}
{bgcolor:black} {/color}{align:left}{bgcolor:yellow}{color:black} - This IS includes security measures (e.g., authentication and access controls) to protect USG interests--not {/color}{/bgcolor}{/align}
{bgcolor:black} {/color}{align:left}{bgcolor:yellow}{color:black} for your personal benefit or privacy. {/color}{/bgcolor}{/align}
{bgcolor:black} {/color}{align:left}{bgcolor:yellow}{color:black} {/color}{/bgcolor}{/align}
{bgcolor:black} {/color}{align:left}{bgcolor:yellow}{color:black} - Notwithstanding the above, using this IS does not constitute consent to PM, LE or CI investigative searching {/color}{/bgcolor}{/align}
{bgcolor:black} {/color}{align:left}{bgcolor:yellow}{color:black} or monitoring of the content of privileged communications, or work product, related to personal representation {/color}{/bgcolor}{/align}
{bgcolor:black} {/color}{align:left}{bgcolor:yellow}{color:black} or services by attorneys, psychotherapists, or clergy, and their assistants. Such communications and work {/color}{/bgcolor}{/align}
{bgcolor:black} {/color}{align:left}{bgcolor:yellow}{color:black} product are private and confidential. See User Agreement for details. {/color}{/bgcolor}{/align}
{bgcolor:black} {/color}{align:left}{bgcolor:yellow}{color:black} {/color}{/bgcolor}{/align}
{bgcolor:black} {/color}{bgcolor:dark-grey}{color:black} {/color}{/bgcolor}
{bgcolor:black} {/color}{bgcolor:dark-grey}{color:black} {/color}{/bgcolor}
{bgcolor:black} {/color}{bgcolor:dark-grey}{color:black} {/color}{/bgcolor}
{bgcolor:black} {/color}{bgcolor:dark-grey}{color:black} {/color}{/bgcolor}
{bgcolor:black} {/color}{bgcolor:dark-grey}{color:black} {/color}{/bgcolor}
{bgcolor:black} {/color}{bgcolor:dark-grey}{color:black} {/color}{/bgcolor}
{bgcolor:black} {/color}{bgcolor:dark-grey}{color:black} {/color}{/bgcolor}
{bgcolor:black} {/color}{bgcolor:dark-grey}{color:black} {/color}{/bgcolor}
{bgcolor:black} {/color}{bgcolor:dark-grey}{color:black} {/color}{/bgcolor}
{bgcolor:black} {/color}{bgcolor:dark-grey}{color:black} {/color}{/bgcolor}
{bgcolor:black} {/color}{bgcolor:dark-grey}{color:black} {/color}{/bgcolor}
{bgcolor:black} {/color}{bgcolor:dark-grey}{color:black} {/color}{/bgcolor}
{bgcolor:black} {/color}{bgcolor:dark-grey}{color:black} {/color}{/bgcolor}
{bgcolor:black} {/color}{bgcolor:dark-grey}{color:black} {/color}{/bgcolor}
{bgcolor:black} {/color}{bgcolor:dark-grey}{color:black} {/color}{/bgcolor}
{bgcolor:black} {/color}{bgcolor:dark-grey}{color:black} {/color}{/bgcolor}
{bgcolor:black} {/color}{bgcolor:dark-grey}{color:black} {/color}{/bgcolor}
{bgcolor:black} {/color}{align:left}{bgcolor:dark-grey}{color:white} <F2> Accept Conditions and Customize System / View Logs{/align}{align:right}<F12> Accept Conditions and Shut Down/Restart {bgcolor:black} {/color}{/color}{/bgcolor}{/align}
{bgcolor:black} {/color}{bgcolor:dark-grey}{color:black} {/color}{/bgcolor}
"@

Get-VMHost | Get-AdvancedSetting -Name Annotations.WelcomeMessage | Set-AdvancedSetting -Value $value

<script end>
References:
  • CCI-000048

STIG ID:
ESXI-65-000008		 Group ID:
V-93963		 Rule ID:
SV-104049r1_rule		 Severity:
CAT II
Requirement: The ESXi host must display the Standard Mandatory DoD Notice and Consent Banner before granting access to the system.
Discussion: Failure to display the DoD logon banner prior to a log in attempt will negate legal proceedings resulting from unauthorized access to system resources.
Check: From the vSphere Web Client select the ESXi Host and go to Configure >> System >> Advanced System Settings. Select the Config.Etc.issue value and verify it is set to DoD logon banner below.

or

From a PowerCLI command prompt while connected to the ESXi host run the following command:

Get-VMHost | Get-AdvancedSetting -Name Config.Etc.issue

If the Config.Etc.issue setting (/etc/issue file) does not contain the logon banner exactly as shown below this is a finding.

"You are accessing a U.S. Government (USG) Information System (IS) that is provided for USG-authorized use only. By using this IS (which includes any device attached to this IS), you consent to the following conditions: -The USG routinely intercepts and monitors communications on this IS for purposes including, but not limited to, penetration testing, COMSEC monitoring, network operations and defense, personnel misconduct (PM), law enforcement (LE), and counterintelligence (CI) investigations. -At any time, the USG may inspect and seize data stored on this IS. -Communications using, or data stored on, this IS are not private, are subject to routine monitoring, interception, and search, and may be disclosed or used for any USG-authorized purpose. -This IS includes security measures (e.g., authentication and access controls) to protect USG interests--not for your personal benefit or privacy. -Notwithstanding the above, using this IS does not constitute consent to PM, LE or CI investigative searching or monitoring of the content of privileged communications, or work product, related to personal representation or services by attorneys, psychotherapists, or clergy, and their assistants. Such communications and work product are private and confidential. See User Agreement for details."
Fix: From the vSphere Web Client select the ESXi Host and go to Configure >> System >> Advanced System Settings. Click Edit and select the Config.Etc.issue value and set it to the following.

"You are accessing a U.S. Government (USG) Information System (IS) that is provided for USG-authorized use only. By using this IS (which includes any device attached to this IS), you consent to the following conditions: -The USG routinely intercepts and monitors communications on this IS for purposes including, but not limited to, penetration testing, COMSEC monitoring, network operations and defense, personnel misconduct (PM), law enforcement (LE), and counterintelligence (CI) investigations. -At any time, the USG may inspect and seize data stored on this IS. -Communications using, or data stored on, this IS are not private, are subject to routine monitoring, interception, and search, and may be disclosed or used for any USG-authorized purpose. -This IS includes security measures (e.g., authentication and access controls) to protect USG interests--not for your personal benefit or privacy. -Notwithstanding the above, using this IS does not constitute consent to PM, LE or CI investigative searching or monitoring of the content of privileged communications, or work product, related to personal representation or services by attorneys, psychotherapists, or clergy, and their assistants. Such communications and work product are private and confidential. See User Agreement for details."

or

From a PowerCLI command prompt while connected to the ESXi host run the following commands:

Get-VMHost | Get-AdvancedSetting -Name Config.Etc.issue | Set-AdvancedSetting -Value "<insert logon banner>"
References:
  • CCI-000048

STIG ID:
ESXI-65-000009		 Group ID:
V-93965		 Rule ID:
SV-104051r1_rule		 Severity:
CAT II
Requirement: The ESXi host SSH daemon must be configured with the Department of Defense (DoD) login banner.
Discussion: The warning message reinforces policy awareness during the logon process and facilitates possible legal action against attackers. Alternatively, systems whose ownership should not be obvious should ensure usage of a banner that does not provide easy attribution.
Check: From an SSH session connected to the ESXi host, or from the ESXi shell, run the following command:

# grep -i "^Banner" /etc/ssh/sshd_config

If there is no output or the output is not exactly "Banner /etc/issue", this is a finding.
Fix: From an SSH session connected to the ESXi host, or from the ESXi shell, add or correct the following line in "/etc/ssh/sshd_config":

Banner /etc/issue
References:
  • CCI-000048

STIG ID:
ESXI-65-000010		 Group ID:
V-93967		 Rule ID:
SV-104053r1_rule		 Severity:
CAT II
Requirement: The ESXi host SSH daemon must use DoD-approved encryption to protect the confidentiality of remote access sessions.
Discussion: Approved algorithms should impart some level of confidence in their implementation. Limit the ciphers to those algorithms which are FIPS-approved. Counter (CTR) mode is also preferred over cipher-block chaining (CBC) mode.

Note: This does not imply FIPS 140-2 validation.
Check: Only FIPS-approved ciphers should be used. To verify that only FIPS-approved ciphers are in use, run the following command from an SSH session connected to the ESXi host, or from the ESXi shell:

# grep -i "^Ciphers" /etc/ssh/sshd_config

If there is no output or the output is not exactly "Ciphers aes128-ctr,aes192-ctr,aes256-ctr", this is a finding.
Fix: Limit the ciphers to those algorithms which are FIPS-approved. Counter (CTR) mode is also preferred over cipher-block chaining (CBC) mode.

From an SSH session connected to the ESXi host, or from the ESXi shell, add or correct the following line in "/etc/ssh/sshd_config":

Ciphers aes128-ctr,aes192-ctr,aes256-ctr
References:
  • CCI-000068

STIG ID:
ESXI-65-000011		 Group ID:
V-93969		 Rule ID:
SV-104055r1_rule		 Severity:
CAT I
Requirement: The ESXi host SSH daemon must be configured to use only the SSHv2 protocol.
Discussion: SSH protocol version 1 suffers from design flaws that result in security vulnerabilities and should not be used. Only SSH protocol version 2 connections should be permitted.
Check: From an SSH session connected to the ESXi host, or from the ESXi shell, run the following command:

# grep -i "^Protocol" /etc/ssh/sshd_config

If there is no output or the output is not exactly "Protocol 2", this is a finding.
Fix: From an SSH session connected to the ESXi host, or from the ESXi shell, add or correct the following line in "/etc/ssh/sshd_config":

Add or correct the following line in "/etc/ssh/sshd_config":

Protocol 2
References:
  • CCI-000068

STIG ID:
ESXI-65-000012		 Group ID:
V-93971		 Rule ID:
SV-104057r1_rule		 Severity:
CAT II
Requirement: The ESXi host SSH daemon must ignore .rhosts files.
Discussion: SSH trust relationships mean a compromise on one host can allow an attacker to move trivially to other hosts. SSH can emulate the behavior of the obsolete rsh command in allowing users to enable insecure access to their accounts via ".rhosts" files.
Check: From an SSH session connected to the ESXi host, or from the ESXi shell, run the following command:

# grep -i "^IgnoreRhosts" /etc/ssh/sshd_config

If there is no output or the output is not exactly "IgnoreRhosts yes", this is a finding.
Fix: From an SSH session connected to the ESXi host, or from the ESXi shell, add or correct the following line in "/etc/ssh/sshd_config":

Add or correct the following line in "/etc/ssh/sshd_config":

IgnoreRhosts yes
References:
  • CCI-000767

STIG ID:
ESXI-65-000013		 Group ID:
V-93973		 Rule ID:
SV-104059r1_rule		 Severity:
CAT II
Requirement: The ESXi host SSH daemon must not allow host-based authentication.
Discussion: SSH trust relationships mean a compromise on one host can allow an attacker to move trivially to other hosts. SSH's cryptographic host-based authentication is more secure than ".rhosts" authentication, since hosts are cryptographically authenticated. However, it is not recommended that hosts unilaterally trust one another, even within an organization.
Check: From an SSH session connected to the ESXi host, or from the ESXi shell, run the following command:

# grep -i "^HostbasedAuthentication" /etc/ssh/sshd_config

If there is no output or the output is not exactly "HostbasedAuthentication no", this is a finding.
Fix: From an SSH session connected to the ESXi host, or from the ESXi shell, add or correct the following line in "/etc/ssh/sshd_config":

Add or correct the following line in "/etc/ssh/sshd_config":

HostbasedAuthentication no
References:
  • CCI-000366

STIG ID:
ESXI-65-000014		 Group ID:
V-93975		 Rule ID:
SV-104061r1_rule		 Severity:
CAT III
Requirement: The ESXi host SSH daemon must not permit root logins.
Discussion: Permitting direct root login reduces auditable information about who ran privileged commands on the system and also allows direct attack attempts on root's password.
Check: From an SSH session connected to the ESXi host, or from the ESXi shell, run the following command:

# grep -i "^PermitRootLogin" /etc/ssh/sshd_config

If there is no output or the output is not exactly "PermitRootLogin no", this is a finding.
Fix: From an SSH session connected to the ESXi host, or from the ESXi shell, add or correct the following line in "/etc/ssh/sshd_config":

Add or correct the following line in "/etc/ssh/sshd_config":

PermitRootLogin no
References:
  • CCI-000366

STIG ID:
ESXI-65-000015		 Group ID:
V-93977		 Rule ID:
SV-104063r1_rule		 Severity:
CAT I
Requirement: The ESXi host SSH daemon must not allow authentication using an empty password.
Discussion: Configuring this setting for the SSH daemon provides additional assurance that remote login via SSH will require a password, even in the event of misconfiguration elsewhere.
Check: From an SSH session connected to the ESXi host, or from the ESXi shell, run the following command:

# grep -i "^PermitEmptyPasswords" /etc/ssh/sshd_config

If there is no output or the output is not exactly "PermitEmptyPasswords no", this is a finding.
Fix: From an SSH session connected to the ESXi host, or from the ESXi shell, add or correct the following line in "/etc/ssh/sshd_config":

PermitEmptyPasswords no
References:
  • CCI-000366

STIG ID:
ESXI-65-000016		 Group ID:
V-93979		 Rule ID:
SV-104065r1_rule		 Severity:
CAT II
Requirement: The ESXi host SSH daemon must not permit user environment settings.
Discussion: SSH environment options potentially allow users to bypass access restriction in some configurations. Users must not be able to present environment options to the SSH daemon.
Check: From an SSH session connected to the ESXi host, or from the ESXi shell, run the following command:

# grep -i "^PermitUserEnvironment" /etc/ssh/sshd_config

If there is no output or the output is not exactly "PermitUserEnvironment no", this is a finding.
Fix: From an SSH session connected to the ESXi host, or from the ESXi shell, add or correct the following line in "/etc/ssh/sshd_config":

PermitUserEnvironment no
References:
  • CCI-000366

STIG ID:
ESXI-65-000017		 Group ID:
V-93981		 Rule ID:
SV-104067r1_rule		 Severity:
CAT II
Requirement: The ESXi host SSH daemon must be configured to only use Message Authentication Codes (MACs) employing FIPS 140-2 approved cryptographic hash algorithms.
Discussion: DoD information systems are required to use FIPS 140-2 approved cryptographic hash functions.
Check: From an SSH session connected to the ESXi host, or from the ESXi shell, run the following command:

# grep -i "^MACs" /etc/ssh/sshd_config

If there is no output or the output is not exactly "MACs hmac-sha1,hmac-sha2-256,hmac-sha2-512", this is a finding.
Fix: From an SSH session connected to the ESXi host, or from the ESXi shell, add or correct the following line in "/etc/ssh/sshd_config":

MACs hmac-sha1,hmac-sha2-256,hmac-sha2-512
References:
  • CCI-000366

STIG ID:
ESXI-65-000018		 Group ID:
V-93983		 Rule ID:
SV-104069r1_rule		 Severity:
CAT III
Requirement: The ESXi host SSH daemon must not permit GSSAPI authentication.
Discussion: GSSAPI authentication is used to provide additional authentication mechanisms to applications. Allowing GSSAPI authentication through SSH exposes the system’s GSSAPI to remote hosts, increasing the attack surface of the system.
Check: From an SSH session connected to the ESXi host, or from the ESXi shell, run the following command:

# grep -i "^GSSAPIAuthentication" /etc/ssh/sshd_config

If there is no output or the output is not exactly "GSSAPIAuthentication no", this is a finding.
Fix: From an SSH session connected to the ESXi host, or from the ESXi shell, add or correct the following line in "/etc/ssh/sshd_config":

GSSAPIAuthentication no
References:
  • CCI-000366

STIG ID:
ESXI-65-000019		 Group ID:
V-93985		 Rule ID:
SV-104071r1_rule		 Severity:
CAT III
Requirement: The ESXi host SSH daemon must not permit Kerberos authentication.
Discussion: Kerberos authentication for SSH is often implemented using GSSAPI. If Kerberos is enabled through SSH, the SSH daemon provides a means of access to the system's Kerberos implementation. Vulnerabilities in the system's Kerberos implementation may then be subject to exploitation. To reduce the attack surface of the system, the Kerberos authentication mechanism within SSH must be disabled for systems.
Check: From an SSH session connected to the ESXi host, or from the ESXi shell, run the following command:

# grep -i "^KerberosAuthentication" /etc/ssh/sshd_config

If there is no output or the output is not exactly "KerberosAuthentication no", this is a finding.
Fix: From an SSH session connected to the ESXi host, or from the ESXi shell, add or correct the following line in "/etc/ssh/sshd_config":

KerberosAuthentication no
References:
  • CCI-000366

STIG ID:
ESXI-65-000020		 Group ID:
V-93987		 Rule ID:
SV-104073r1_rule		 Severity:
CAT II
Requirement: The ESXi host SSH daemon must perform strict mode checking of home directory configuration files.
Discussion: If other users have access to modify user-specific SSH configuration files, they may be able to log into the system as another user.
Check: From an SSH session connected to the ESXi host, or from the ESXi shell, run the following command:

# grep -i "^StrictModes" /etc/ssh/sshd_config

If there is no output or the output is not exactly "StrictModes yes", this is a finding.
Fix: From an SSH session connected to the ESXi host, or from the ESXi shell, add or correct the following line in "/etc/ssh/sshd_config":

StrictModes yes
References:
  • CCI-000366

STIG ID:
ESXI-65-000021		 Group ID:
V-93989		 Rule ID:
SV-104075r1_rule		 Severity:
CAT II
Requirement: The ESXi host SSH daemon must not allow compression or must only allow compression after successful authentication.
Discussion: If compression is allowed in an SSH connection prior to authentication, vulnerabilities in the compression software could result in compromise of the system from an unauthenticated connection, potentially with root privileges.
Check: From an SSH session connected to the ESXi host, or from the ESXi shell, run the following command:

# grep -i "^Compression" /etc/ssh/sshd_config

If there is no output or the output is not exactly "Compression no", this is a finding.
Fix: From an SSH session connected to the ESXi host, or from the ESXi shell, add or correct the following line in "/etc/ssh/sshd_config":

Compression no
References:
  • CCI-000366

STIG ID:
ESXI-65-000022		 Group ID:
V-93991		 Rule ID:
SV-104077r1_rule		 Severity:
CAT III
Requirement: The ESXi host SSH daemon must be configured to not allow gateway ports.
Discussion: SSH TCP connection forwarding provides a mechanism to establish TCP connections proxied by the SSH server. This function can provide similar convenience to a Virtual Private Network (VPN) with the similar risk of providing a path to circumvent firewalls and network ACLs. Gateway ports allow remote forwarded ports to bind to non-loopback addresses on the server.
Check: From an SSH session connected to the ESXi host, or from the ESXi shell, run the following command:

# grep -i "^GatewayPorts" /etc/ssh/sshd_config

If there is no output or the output is not exactly "GatewayPorts no", this is a finding.
Fix: From an SSH session connected to the ESXi host, or from the ESXi shell, add or correct the following line in "/etc/ssh/sshd_config":

GatewayPorts no
References:
  • CCI-000366

STIG ID:
ESXI-65-000023		 Group ID:
V-93993		 Rule ID:
SV-104079r1_rule		 Severity:
CAT II
Requirement: The ESXi host SSH daemon must be configured to not allow X11 forwarding.
Discussion: X11 forwarding over SSH allows for the secure remote execution of X11-based applications. This feature can increase the attack surface of an SSH connection.
Check: From an SSH session connected to the ESXi host, or from the ESXi shell, run the following command:

# grep -i "^X11Forwarding" /etc/ssh/sshd_config

If there is no output or the output is not exactly "X11Forwarding no", this is a finding.
Fix: From an SSH session connected to the ESXi host, or from the ESXi shell, add or correct the following line in "/etc/ssh/sshd_config":

X11Forwarding no
References:
  • CCI-000366

STIG ID:
ESXI-65-000024		 Group ID:
V-93995		 Rule ID:
SV-104081r1_rule		 Severity:
CAT II
Requirement: The ESXi host SSH daemon must not accept environment variables from the client.
Discussion: Environment variables can be used to change the behavior of remote sessions and should be limited. Locale environment variables that specify the language, character set, and other features modifying the operation of software to match the user's preferences.
Check: From an SSH session connected to the ESXi host, or from the ESXi shell, run the following command:

# grep -i "^AcceptEnv" /etc/ssh/sshd_config

If there is no output or the output is not exactly "AcceptEnv", this is a finding.
Fix: From an SSH session connected to the ESXi host, or from the ESXi shell, add or correct the following line in "/etc/ssh/sshd_config":

AcceptEnv
References:
  • CCI-000366

STIG ID:
ESXI-65-000025		 Group ID:
V-93997		 Rule ID:
SV-104083r1_rule		 Severity:
CAT II
Requirement: The ESXi host SSH daemon must not permit tunnels.
Discussion: OpenSSH has the ability to create network tunnels (layer-2 and layer-3) over an SSH connection. This function can provide similar convenience to a Virtual Private Network (VPN) with the similar risk of providing a path to circumvent firewalls and network ACLs.
Check: From an SSH session connected to the ESXi host, or from the ESXi shell, run the following command:

# grep -i "^PermitTunnel" /etc/ssh/sshd_config

If there is no output or the output is not exactly "PermitTunnel no", this is a finding.
Fix: From an SSH session connected to the ESXi host, or from the ESXi shell, add or correct the following line in "/etc/ssh/sshd_config":

PermitTunnel no
References:
  • CCI-000366

STIG ID:
ESXI-65-000026		 Group ID:
V-93999		 Rule ID:
SV-104085r1_rule		 Severity:
CAT III
Requirement: The ESXi host SSH daemon must set a timeout count on idle sessions.
Discussion: This ensures a user login will be terminated as soon as the "ClientAliveCountMax" is reached.
Check: From an SSH session connected to the ESXi host, or from the ESXi shell, run the following command:

# grep -i "^ClientAliveCountMax" /etc/ssh/sshd_config

If there is no output or the output is not exactly "ClientAliveCountMax 3", this is a finding.
Fix: From an SSH session connected to the ESXi host, or from the ESXi shell, add or correct the following line in "/etc/ssh/sshd_config":

ClientAliveCountMax 3
References:
  • CCI-000366

STIG ID:
ESXI-65-000027		 Group ID:
V-94001		 Rule ID:
SV-104087r1_rule		 Severity:
CAT III
Requirement: The ESXi hostSSH daemon must set a timeout interval on idle sessions.
Discussion: Causing idle users to be automatically logged out guards against compromises one system leading trivially to compromises on another.
Check: From an SSH session connected to the ESXi host, or from the ESXi shell, run the following command:

# grep -i "^ClientAliveInterval" /etc/ssh/sshd_config

If there is no output or the output is not exactly "ClientAliveInterval 200", this is a finding.
Fix: From an SSH session connected to the ESXi host, or from the ESXi shell, add or correct the following line in "/etc/ssh/sshd_config":

ClientAliveInterval 200
References:
  • CCI-000366

STIG ID:
ESXI-65-000028		 Group ID:
V-94003		 Rule ID:
SV-104089r1_rule		 Severity:
CAT II
Requirement: The ESXi host SSH daemon must limit connections to a single session.
Discussion: The SSH protocol has the ability to provide multiple sessions over a single connection without reauthentication. A compromised client could use this feature to establish additional sessions to a system without consent or knowledge of the user.
Check: From an SSH session connected to the ESXi host, or from the ESXi shell, run the following command:

# grep -i "^MaxSessions" /etc/ssh/sshd_config

If there is no output or the output is not exactly "MaxSessions 1", this is a finding.
Fix: From an SSH session connected to the ESXi host, or from the ESXi shell, add or correct the following line in "/etc/ssh/sshd_config":

MaxSessions 1
References:
  • CCI-000366

STIG ID:
ESXI-65-000029		 Group ID:
V-94005		 Rule ID:
SV-104091r1_rule		 Severity:
CAT II
Requirement: The ESXi host must remove keys from the SSH authorized_keys file.
Discussion: ESXi hosts come with SSH which can be enabled to allow remote access without requiring user authentication.  To enable password free access copy the remote users public key into the "/etc/ssh/keys-root/authorized_keys" file on the ESXi host.  The presence of the remote user's public key in the "authorized_keys" file identifies the user as trusted, meaning the user is granted access to the host without providing a password.  If using Lockdown Mode and SSH is disabled then login with authorized keys will have the same restrictions as username/password.
Check: From an SSH session connected to the ESXi host, or from the ESXi shell, run the following command:

# ls -la /etc/ssh/keys-root/authorized_keys

or

# cat /etc/ssh/keys-root/authorized_keys

If the authorized_keys file exists and is not empty, this is a finding.
Fix: From an SSH session connected to the ESXi host, or from the ESXi shell, zero or remove the /etc/ssh/keys-root/authorized_keys file:

# >/etc/ssh/keys-root/authorized_keys

or

# rm /etc/ssh/keys-root/authorized_keys
References:
  • CCI-000366

STIG ID:
ESXI-65-000030		 Group ID:
V-94007		 Rule ID:
SV-104093r1_rule		 Severity:
CAT III
Requirement: The ESXi host must produce audit records containing information to establish what type of events occurred.
Discussion: Without establishing what types of events occurred, it would be difficult to establish, correlate, and investigate the events leading up to an outage or attack.
Check: From the vSphere Web Client select the ESXi Host and go to Configure >> System >> Advanced System Settings. Select the Config.HostAgent.log.level value and verify it is set to "info".

or

From a PowerCLI command prompt while connected to the ESXi host run the following command:

Get-VMHost | Get-AdvancedSetting -Name Config.HostAgent.log.level

If the Config.HostAgent.log.level setting is not set to info, this is a finding.

Note: Verbose logging level is acceptable for troubleshooting purposes.
Fix: From the vSphere Web Client select the ESXi Host and go to Configure >> System >> Advanced System Settings. Click Edit and select the Config.HostAgent.log.level value and configure it to "info".

or

From a PowerCLI command prompt while connected to the ESXi host run the following commands:

Get-VMHost | Get-AdvancedSetting -Name Config.HostAgent.log.level | Set-AdvancedSetting -Value "info"
References:
  • CCI-000130

STIG ID:
ESXI-65-000031		 Group ID:
V-94009		 Rule ID:
SV-104095r1_rule		 Severity:
CAT II
Requirement: The ESXi host must enforce password complexity by requiring that at least one upper-case character be used.
Discussion: To enforce the use of complex passwords, minimum numbers of characters of different classes are mandated. The use of complex passwords reduces the ability of attackers to successfully obtain valid passwords using guessing or exhaustive search techniques. Complexity requirements increase the password search space by requiring users to construct passwords from a larger character set than they may otherwise use.
Check: From the vSphere Web Client select the ESXi Host and go to Configure >> System >> Advanced System Settings. Select the Security.PasswordQualityControl value and verify it is set to "similar=deny retry=3 min=disabled,disabled,disabled,disabled,15"

or

From a PowerCLI command prompt while connected to the ESXi host run the following command:

Get-VMHost | Get-AdvancedSetting -Name Security.PasswordQualityControl

If the Security.PasswordQualityControl setting is not set to "similar=deny retry=3 min=disabled,disabled,disabled,disabled,15", this is a finding.
Fix: From the vSphere Web Client select the ESXi Host and go to Configure >> System >> Advanced System Settings. Click Edit and select the Security.PasswordQualityControl value and configure it to "similar=deny retry=3 min=disabled,disabled,disabled,disabled,15".

or

From a PowerCLI command prompt while connected to the ESXi host run the following commands:

Get-VMHost | Get-AdvancedSetting -Name Security.PasswordQualityControl | Set-AdvancedSetting -Value "similar=deny retry=3 min=disabled,disabled,disabled,disabled,15"
References:
  • CCI-000192

STIG ID:
ESXI-65-000032		 Group ID:
V-94011		 Rule ID:
SV-104097r1_rule		 Severity:
CAT II
Requirement: The ESXi host must prohibit the reuse of passwords within five iterations.
Discussion: If a user, or root, used the same password continuously or was allowed to change it back shortly after being forced to change it to something else, it would provide a potential intruder with the opportunity to keep guessing at one user's password until it was guessed correctly.
Check: From an SSH session connected to the ESXi host, or from the ESXi shell, run the following command:

# grep -i "^password" /etc/pam.d/passwd | grep sufficient

If the remember setting is not set or is not "remember=5", this is a finding.
Fix: From an SSH session connected to the ESXi host, or from the ESXi shell, add or correct the following line in “/etc/pam.d/passwd”:

password sufficient /lib/security/$ISA/pam_unix.so use_authtok nullok shadow sha512 remember=5
References:
  • CCI-000200

STIG ID:
ESXI-65-000033		 Group ID:
V-94013		 Rule ID:
SV-104099r1_rule		 Severity:
CAT II
Requirement: The password hashes stored on the ESXi host must have been generated using a FIPS 140-2 approved cryptographic hashing algorithm.
Discussion: Systems must employ cryptographic hashes for passwords using the SHA-2 family of algorithms or FIPS 140-2 approved successors. The use of unapproved algorithms may result in weak password hashes more vulnerable to compromise.
Check: From an SSH session connected to the ESXi host, or from the ESXi shell, run the following command:

# grep -i "^password" /etc/pam.d/passwd | grep sufficient

If sha512 is not listed, this is a finding.
Fix: From an SSH session connected to the ESXi host, or from the ESXi shell, add or correct the following line in “/etc/pam.d/passwd”:

password sufficient /lib/security/$ISA/pam_unix.so use_authtok nullok shadow sha512 remember=5
References:
  • CCI-000366

STIG ID:
ESXI-65-000034		 Group ID:
V-94015		 Rule ID:
SV-104101r1_rule		 Severity:
CAT II
Requirement: The ESXi host must disable the Managed Object Browser (MOB).
Discussion: The Managed Object Browser (MOB) provides a way to explore the object model used by the VMkernel to manage the host and enables configurations to be changed as well. This interface is meant to be used primarily for debugging the vSphere SDK, but because there are no access controls it could also be used as a method obtain information about a host being targeted for unauthorized access. By default this is disabled for ESXi in version 6.
Check: From the vSphere Web Client select the ESXi Host and go to Configure >> System >> Advanced System Settings. Select the Config.HostAgent.plugins.solo.enableMob value and verify it is set to false.

or

From a PowerCLI command prompt while connected to the ESXi host run the following command:

Get-VMHost | Get-AdvancedSetting -Name Config.HostAgent.plugins.solo.enableMob

If the Config.HostAgent.plugins.solo.enableMob setting is not set to false, this is a finding.
Fix: From the vSphere Web Client select the ESXi Host and go to Configure >> System >> Advanced System Settings. Click Edit and select the Config.HostAgent.plugins.solo.enableMob value and configure it to false.

or

From a PowerCLI command prompt while connected to the ESXi host run the following commands:

Get-VMHost | Get-AdvancedSetting -Name Config.HostAgent.plugins.solo.enableMob | Set-AdvancedSetting -Value false
References:
  • CCI-000381

STIG ID:
ESXI-65-000035		 Group ID:
V-94017		 Rule ID:
SV-104103r1_rule		 Severity:
CAT II
Requirement: The ESXi host must be configured to disable non-essential capabilities by disabling SSH.
Discussion: The ESXi Shell is an interactive command line interface (CLI) available at the ESXi server console. The ESXi shell provides temporary access to commands essential for server maintenance. Intended primarily for use in break-fix scenarios, the ESXi shell is well suited for checking and modifying configuration details, not always generally accessible, using the vSphere Client. The ESXi shell is accessible remotely using SSH by users with the Administrator role. Under normal operating conditions, SSH access to the host must be disabled as is the default. As with the ESXi shell, SSH is also intended only for temporary use during break-fix scenarios. SSH must therefore be disabled under normal operating conditions and must only be enabled for diagnostics or troubleshooting. Remote access to the host must therefore be limited to the vSphere Client at all other times.
Check: From the vSphere Web Client select the ESXi Host and go to Configure >> System >> Security Profile. Under Services select Edit and view the "SSH" service and verify it is stopped.

or

From a PowerCLI command prompt while connected to the ESXi host run the following command:

Get-VMHost | Get-VMHostService | Where {$_.Label -eq "SSH"}

If the ESXi SSH service is running, this is a finding.
Fix: From the vSphere Web Client select the ESXi Host and go to Configure >> System >> Security Profile. Under Services select Edit then select the SSH service and click the Stop button to stop the service. Use the pull-down menu to change the Startup policy to "Start and stop manually" and click OK.

or

From a PowerCLI command prompt while connected to the ESXi host run the following commands:

Get-VMHost | Get-VMHostService | Where {$_.Label -eq "SSH"} | Set-VMHostService -Policy Off
Get-VMHost | Get-VMHostService | Where {$_.Label -eq "SSH"} | Stop-VMHostService
References:
  • CCI-000381

STIG ID:
ESXI-65-000036		 Group ID:
V-94019		 Rule ID:
SV-104105r1_rule		 Severity:
CAT II
Requirement: The ESXi host must disable ESXi Shell unless needed for diagnostics or troubleshooting.
Discussion: The ESXi Shell is an interactive command line environment available locally from the DCUI or remotely via SSH. Activities performed from the ESXi Shell bypass vCenter RBAC and audit controls. The ESXi shell should only be turned on when needed to troubleshoot/resolve problems that cannot be fixed through the vSphere client.
Check: From the vSphere Web Client select the ESXi Host and go to Configure >> System >> Security Profile. Under Services select Edit and view the "ESXi Shell" service and verify it is stopped.

or

From a PowerCLI command prompt while connected to the ESXi host run the following command:

Get-VMHost | Get-VMHostService | Where {$_.Label -eq "ESXi Shell"}

If the ESXi Shell service is running, this is a finding.
Fix: From the vSphere Web Client select the ESXi Host and go to Configure >> System >> Security Profile. Under Services select Edit then select the ESXi Shell service and click the Stop button to stop the service. Use the pull-down menu to change the Startup policy to "Start and stop manually" and click OK.

or

From a PowerCLI command prompt while connected to the ESXi host run the following commands:

Get-VMHost | Get-VMHostService | Where {$_.Label -eq "ESXi Shell"} | Set-VMHostService -Policy Off
Get-VMHost | Get-VMHostService | Where {$_.Label -eq "ESXi Shell"} | Stop-VMHostService
References:
  • CCI-000381

STIG ID:
ESXI-65-000037		 Group ID:
V-94021		 Rule ID:
SV-104107r1_rule		 Severity:
CAT III
Requirement: The ESXi host must use Active Directory for local user authentication.
Discussion: Join ESXi hosts to an Active Directory (AD) domain to eliminate the need to create and maintain multiple local user accounts. Using AD for user authentication simplifies the ESXi host configuration, ensures password complexity and reuse policies are enforced and reduces the risk of security breaches and unauthorized access. Note: If the AD group "ESX Admins" (default) exists then all users and groups that are assigned as members to this group will have full administrative access to all ESXi hosts the domain.
Check: From the vSphere Web Client select the ESXi Host and go to Configure >> System >> Authentication Services. Verify the Directory Services Type is set to Active Directory.

or

From a PowerCLI command prompt while connected to the ESXi host run the following command:

Get-VMHost | Get-VMHostAuthentication

For systems that do not use Active Directory and have no local user accounts, other than root and/or vpxuser, this is not applicable.

For systems that do not use Active Directory and do have local user accounts, other than root and/or vpxuser, this is a finding.

If the Directory Services Type is not set to "Active Directory", this is a finding.
Fix: From the vSphere Web Client select the ESXi Host and go to Configure >> System >> Authentication Services. Click Join Domain and enter the AD domain to join, select the "Using credentials” radio button and enter the credentials of an account with permissions to join machines to AD (use UPN naming – user@domain) and then click OK.

or

From a PowerCLI command prompt while connected to the ESXi host run the following command:

Get-VMHost | Get-VMHostAuthentication | Set-VMHostAuthentication -JoinDomain -Domain "domain name" -User "username" -Password "password"
References:
  • CCI-000764

STIG ID:
ESXI-65-000038		 Group ID:
V-94023		 Rule ID:
SV-104109r2_rule		 Severity:
CAT II
Requirement: The ESXi host must use the vSphere Authentication Proxy to protect passwords when adding ESXi hosts to Active Directory.
Discussion: If you configure your host to join an Active Directory domain using Host Profiles the Active Directory credentials are saved in the host profile and are transmitted over the network. To avoid having to save Active Directory credentials in the Host Profile and to avoid transmitting Active Directory credentials over the network use the vSphere Authentication Proxy.
Check: From the vSphere Web Client go to Home >> Host Profiles >> and select a Host Profile to edit. View the settings under Security and Services >> Security Settings >> Authentication Configuration >> Active Directory Configuration >> Join Domain Method. Verify the method used to join hosts to a domain is set to "Use vSphere Authentication Proxy to add the host to domain".

or

From a PowerCLI command prompt while connected to vCenter run the following command:

Get-VMHost | Select Name, ` @{N="HostProfile";E={$_ | Get-VMHostProfile}}, ` @{N="JoinADEnabled";E={($_ | Get-VmHostProfile).ExtensionData.Config.ApplyProfile.Authentication.ActiveDirectory.Enabled}}, ` @{N="JoinDomainMethod";E={(($_ | Get-VMHostProfile).ExtensionData.Config.ApplyProfile.Authentication.ActiveDirectory | Select -ExpandProperty Policy | Where {$_.Id -eq "JoinDomainMethodPolicy"}).Policyoption.Id}}

Verify if JoinADEnabled is True then JoinDomainMethod should be "FixedCAMConfigOption".

If you are not using Host Profiles to join active directory, this is not a finding.
Fix: From the vSphere Web Client go to Home >> Host Profiles >> and select a Host Profile to edit. View the settings under Security and Services >> Security Settings >> Authentication Configuration >> Active Directory Configuration >> Join Domain Method. Set the method used to join hosts to a domain to "Use vSphere Authentication Proxy to add the host to domain" and provide the IP address of the vSphere Authentication Proxy server.
References:
  • CCI-000764

STIG ID:
ESXI-65-000039		 Group ID:
V-94025		 Rule ID:
SV-104111r1_rule		 Severity:
CAT III
Requirement: Active Directory ESX Admin group membership must not be used when adding ESXi hosts to Active Directory.
Discussion: When adding ESXi hosts to Active Directory, if the group "ESX Admins" exists, all user/group accounts assigned to the group will have full administrative access to the host. Discretion should be used when managing membership to the "ESX Admins" group.
Check: From the vSphere Web Client select the ESXi Host and go to Configuration >> System >> Advanced System Settings. Click Edit and select the Config.HostAgent.plugins.hostsvc.esxAdminsGroup value and verify it is not set to "ESX Admins".

or

From a PowerCLI command prompt while connected to the ESXi host run the following command:

Get-VMHost | Get-AdvancedSetting -Name Config.HostAgent.plugins.hostsvc.esxAdminsGroup

For systems that do not use Active Directory and have no local user accounts, other than root and/or vpxuser, this is not applicable.

For systems that do not use Active Directory and do have local user accounts, other than root and/or vpxuser, this is a finding.

If the "Config.HostAgent.plugins.hostsvc.esxAdminsGroup" keyword is set to "ESX Admins", this is a finding.
Fix: From the vSphere Web Client select the ESXi Host and go to Configuration >> System >> Advanced System Settings. Click Edit and select the Config.HostAgent.plugins.hostsvc.esxAdminsGroup value and configure it to an Active Directory group other than "ESX Admins".

or

From a PowerCLI command prompt while connected to the ESXi host run the following commands:

Get-VMHost | Get-AdvancedSetting -Name Config.HostAgent.plugins.hostsvc.esxAdminsGroup | Set-AdvancedSetting -Value <AD Group>
References:
  • CCI-000764

STIG ID:
ESXI-65-000040		 Group ID:
V-94027		 Rule ID:
SV-104113r1_rule		 Severity:
CAT III
Requirement: The ESXi host must use multifactor authentication for local access to privileged accounts.
Discussion: To assure accountability and prevent unauthenticated access, privileged users must utilize multifactor authentication to prevent potential misuse and compromise of the system.
Check: From the vSphere Web Client select the ESXi Host and go to Configure >> System >> Authentication Services and view the Smart Card Authentication status. If "Enable Smart Card Authentication" is checked, the system requires smart cards to authentication to an Active Directory Domain.

For systems that have no local user accounts, other than root and/or vpxuser, this is not applicable.

For environments that do not use vCenter server to manage ESXi, this is not applicable.

For systems that do not use smart cards with Active Directory and do have local user accounts, other than root and/or vpxuser, this is a finding.
Fix: The following are pre-requisites to configuration smart card authentication for the ESXi DCUI:
-Active Directory domain that supports smart card authentication, smart card readers, and smart cards.
-ESXi joined to an Active Directory domain.
-Trusted certificates for root and intermediary certificate authorities.

From the vSphere Web Client select the ESXi Host and go to Configure >> System >> Authentication Services and click Edit and check "Enable Smart Card Authentication" checkbox, at the Certificates tab, click the green plus sign to import trusted certificate authority certificates and click OK.
References:
  • CCI-000767

STIG ID:
ESXI-65-000041		 Group ID:
V-94029		 Rule ID:
SV-104115r1_rule		 Severity:
CAT II
Requirement: The ESXi host must set a timeout to automatically disable idle sessions after 10 minutes.
Discussion: If a user forgets to log out of their SSH session, the idle connection will remains open indefinitely, increasing the potential for someone to gain privileged access to the host. The ESXiShellInteractiveTimeOut allows you to automatically terminate idle shell sessions.
Check: From the vSphere Web Client select the ESXi Host and go to Configure >> System >> Advanced System Settings. Select the UserVars.ESXiShellInteractiveTimeOut value and verify it is set to 600 (10 Minutes).

or

From a PowerCLI command prompt while connected to the ESXi host run the following command:

Get-VMHost | Get-AdvancedSetting -Name UserVars.ESXiShellInteractiveTimeOut

If the UserVars.ESXiShellInteractiveTimeOut setting is not set to 600, this is a finding.
Fix: From the vSphere Web Client select the ESXi Host and go to Configure >> System >> Advanced System Settings. Click Edit and select the UserVars.ESXiShellInteractiveTimeOut value and configure it to 600.

or

From a PowerCLI command prompt while connected to the ESXi host run the following commands:

Get-VMHost | Get-AdvancedSetting -Name UserVars.ESXiShellInteractiveTimeOut | Set-AdvancedSetting -Value 600
References:
  • CCI-001133

STIG ID:
ESXI-65-000042		 Group ID:
V-94031		 Rule ID:
SV-104117r1_rule		 Severity:
CAT II
Requirement: The ESXi host must terminate shell services after 10 minutes.
Discussion: When the ESXi Shell or SSH services are enabled on a host they will run indefinitely. To avoid having these services left running set the ESXiShellTimeOut. The ESXiShellTimeOut defines a window of time after which the ESXi Shell and SSH services will automatically be terminated.
Check: From the vSphere Web Client select the ESXi Host and go to Configure >> System >> Advanced System Settings. Select the UserVars.ESXiShellTimeOut value and verify it is set to 600 (10 Minutes).

or

From a PowerCLI command prompt while connected to the ESXi host run the following command:

Get-VMHost | Get-AdvancedSetting -Name UserVars.ESXiShellTimeOut

If the UserVars.ESXiShellTimeOut setting is not set to 600, this is a finding.
Fix: From the vSphere Web Client select the ESXi Host and go to Configure >> System >> Advanced System Settings. Click Edit and select the UserVars.ESXiShellTimeOut value and configure it to 600.

or

From a PowerCLI command prompt while connected to the ESXi host run the following commands:

Get-VMHost | Get-AdvancedSetting -Name UserVars.ESXiShellTimeOut | Set-AdvancedSetting -Value 600
References:
  • CCI-001133

STIG ID:
ESXI-65-000043		 Group ID:
V-94033		 Rule ID:
SV-104119r1_rule		 Severity:
CAT II
Requirement: The ESXi host must logout of the console UI after 10 minutes.
Discussion: When the Direct console user interface (DCUI) is enabled and logged in it should be automatically logged out if left logged in to avoid unauthorized privilege gains. The DcuiTimeOut defines a window of time after which the DCUI will be logged out.
Check: From the vSphere Web Client select the ESXi Host and go to Configure >> System >> Advanced System Settings. Select the UserVars.DcuiTimeOut value and verify it is set to 600 (10 Minutes).

or

From a PowerCLI command prompt while connected to the ESXi host run the following command:

Get-VMHost | Get-AdvancedSetting -Name UserVars.DcuiTimeOut

If the UserVars.DcuiTimeOut setting is not set to 600, this is a finding.
Fix: From the vSphere Web Client select the ESXi Host and go to Configure >> System >> Advanced System Settings. Click Edit and select the UserVars.DcuiTimeOut value and configure it to 600.

or

From a PowerCLI command prompt while connected to the ESXi host run the following commands:

Get-VMHost | Get-AdvancedSetting -Name UserVars.DcuiTimeOut | Set-AdvancedSetting -Value 600
References:
  • CCI-001133

STIG ID:
ESXI-65-000044		 Group ID:
V-94035		 Rule ID:
SV-104121r1_rule		 Severity:
CAT III
Requirement: The ESXi host must enable kernel core dumps.
Discussion: In the event of a system failure, the system must preserve any information necessary to determine cause of failure and any information necessary to return to operations with least disruption to mission processes.
Check: From the vSphere Web Client select the ESXi Host and right click. If the "Add Diagnostic Partition" option is greyed out then core dumps are configured.

or

From a PowerCLI command prompt while connected to the ESXi host run the following commands:

$esxcli = Get-EsxCli
$esxcli.system.coredump.partition.get()
$esxcli.system.coredump.network.get()

The first command prepares for the other two. The second command shows whether there is an active core dump partition configured. The third command shows whether a network core dump collector is configured and enabled, via the "HostVNic", "NetworkServerIP", "NetworkServerPort", and "Enabled" variables.

If there is no active core dump partition or the network core dump collector is not configured and enabled, this is a finding.
Fix: From the vSphere Web Client select the ESXi Host and right click. Select the "Add Diagnostic Partition" option configure a core dump diagnostic partition.

or

From a PowerCLI command prompt while connected to the ESXi host run at least one of the following sets of commands:

To configure a core dump partition:

$esxcli = Get-EsxCli
#View available partitions to configure
$esxcli.system.coredump.partition.list()
$esxcli.system.coredump.partition.set($null,"PartitionName",$null,$null)

To configure a core dump collector:

$esxcli = Get-EsxCli
$esxcli.system.coredump.network.set($null,"vmkernel port to use",$null,"CollectorIP","CollectorPort")
$esxcli.system.coredump.network.set($true)
References:
  • CCI-001665

STIG ID:
ESXI-65-000045		 Group ID:
V-94037		 Rule ID:
SV-104123r1_rule		 Severity:
CAT II
Requirement: The ESXi host must enable a persistent log location for all locally stored logs.
Discussion: ESXi can be configured to store log files on an in-memory file system. This occurs when the host's "/scratch" directory is linked to "/tmp/scratch". When this is done only a single day's worth of logs are stored at any time. In addition log files will be reinitialized upon each reboot. This presents a security risk as user activity logged on the host is only stored temporarily and will not persistent across reboots. This can also complicate auditing and make it harder to monitor events and diagnose issues. ESXi host logging should always be configured to a persistent datastore.

Note: Scratch space is configured automatically during installation or first boot of an ESXi host, and does not usually need to be manually configured. ESXi Installable creates a 4 GB Fat16 partition on the target device during installation if there is sufficient space, and if the device is considered Local. If ESXi is installed on an SD card or USB device a persistent log location may not be configured upon install as normal.
Check: From the vSphere Web Client select the ESXi Host and go to Configure >> System >> Advanced System Settings. Select the Syslog.global.logDir value and verify it is set to a persistent location.

or

From a PowerCLI command prompt while connected to the ESXi host run the following commands:

Get-VMHost | Get-AdvancedSetting -Name Syslog.global.logDir

or

$esxcli = Get-EsxCli
$esxcli.system.syslog.config.get() | Select LocalLogOutput,LocalLogOutputIsPersistent

If the Syslog.global.logDir or LocalLogOutput value is not on persistent storage, this is a finding.

If the LocalLogOutputIsPersistent value is not true, this is a finding.
Fix: From the vSphere Web Client select the ESXi Host and go to Configure >> System >> Advanced System Settings. Click Edit and select the Syslog.global.logDir value and set it to a known persistent location.

or

From a PowerCLI command prompt while connected to the ESXi host run the following commands:

Get-VMHost | Get-AdvancedSetting -Name Syslog.global.logDir | Set-AdvancedSetting -Value "New Log Location"
References:
  • CCI-001849

STIG ID:
ESXI-65-000046		 Group ID:
V-94039		 Rule ID:
SV-104125r1_rule		 Severity:
CAT II
Requirement: The ESXi host must configure NTP time synchronization.
Discussion: To assure the accuracy of the system clock, it must be synchronized with an authoritative time source within DoD. Many system functions, including time-based login and activity restrictions, automated reports, system logs, and audit records depend on an accurate system clock. If there is no confidence in the correctness of the system clock, time-based functions may not operate as intended and records may be of diminished value.
Check: From the vSphere Web Client select the ESXi Host and go to Configure >> System >> Time Configuration. Click Edit to verify the configured NTP servers and service startup policy.

or

From a PowerCLI command prompt while connected to the ESXi host run the following command:

Get-VMHost | Get-VMHostNTPServer
Get-VMHost | Get-VMHostService | Where {$_.Label -eq "NTP Daemon"}

If the NTP service is not configured with authoritative DoD time sources and the service is not configured to start and stop with the host and is running, this is a finding.
Fix: From the vSphere Web Client select the ESXi Host and go to Configure >> System >> Time Configuration. Click Edit to configure the NTP service to start and stop with the host and with authoritative DoD time sources.

or

From a PowerCLI command prompt while connected to the ESXi host run the following command:

$NTPServers = "ntpserver1","ntpserver2"
Get-VMHost | Add-VMHostNTPServer $NTPServers
Get-VMHost | Get-VMHostService | Where {$_.Label -eq "NTP Daemon"} | Set-VMHostService -Policy On
Get-VMHost | Get-VMHostService | Where {$_.Label -eq "NTP Daemon"} | Start-VMHostService
References:
  • CCI-001891

STIG ID:
ESXI-65-000047		 Group ID:
V-94041		 Rule ID:
SV-104127r1_rule		 Severity:
CAT I
Requirement: The ESXi Image Profile and VIB Acceptance Levels must be verified.
Discussion: Verify the ESXi Image Profile to only allow signed VIBs. An unsigned VIB represents untested code installed on an ESXi host. The ESXi Image profile supports four acceptance levels:

(1) VMwareCertified - VIBs created, tested and signed by VMware
(2) VMwareAccepted - VIBs created by a VMware partner but tested and signed by VMware,
(3) PartnerSupported - VIBs created, tested and signed by a certified VMware partner
(4) CommunitySupported - VIBs that have not been tested by VMware or a VMware partner.

Community Supported VIBs are not supported and do not have a digital signature. To protect the security and integrity of your ESXi hosts do not allow unsigned (CommunitySupported) VIBs to be installed on your hosts.
Check: From the vSphere Web Client select the ESXi Host and go to Configure >> System >> Security Profile. Under "Host Image Profile Acceptance Level" view the acceptance level.

or

From a PowerCLI command prompt while connected to the ESXi host run the following commands:

$esxcli = Get-EsxCli
$esxcli.software.acceptance.get()

If the acceptance level is CommunitySupported, this is a finding.
Fix: From the vSphere Web Client select the ESXi Host and go to Configure >> System >> Security Profile. Under "Host Image Profile Acceptance Level" click Edit… and use the pull-down selection, set the acceptance level to be VMwareCertified, VMwareAccepted, or PartnerSupported.

or

From a PowerCLI command prompt while connected to the ESXi host run the following commands:

$esxcli = Get-EsxCli
$esxcli.software.acceptance.Set("PartnerSupported")

Note: VMwareCertified or VMwareAccepted may be substituted for PartnerSupported, depending upon local requirements.
References:
  • CCI-001749

STIG ID:
ESXI-65-000048		 Group ID:
V-94043		 Rule ID:
SV-104129r1_rule		 Severity:
CAT II
Requirement: The ESXi host must protect the confidentiality and integrity of transmitted information by isolating vMotion traffic.
Discussion: While encrypted vMotion is available now vMotion traffic should still be sequestered from other traffic to further protect it from attack. This network must be only be accessible to other ESXi hosts preventing outside access to the network.
Check: The vMotion VMKernel port group should in a dedicated VLAN that can be on a common standard or distributed virtual switch as long as the vMotion VLAN is not shared by any other function and it not routed to anything but ESXi hosts. The check for this will be unique per environment. From the vSphere Client select the ESXi host and go to Configuration > Networking and review the VLAN associated with the vMotion VMkernel(s) and verify they are dedicated for that purpose and are logically separated from other functions.

If long distance or cross vCenter vMotion is used the vMotion network can be routable but must be accessible to only the intended ESXi hosts.

If the vMotion port group is not on an isolated VLAN and/or is routable to systems other than ESXi hosts, this is a finding.

For environments that do not use vCenter server to manage ESXi, this is not applicable.
Fix: Configuration of the vMotion VMkernel will be unique to each environment. As an example, to modify the IP address and VLAN information to the correct network on a distributed switch do the following:

From the vSphere Web Client go to Networking >> Select a distributed switch >> Select a port group >> Configure >> Settings >> Edit >> VLAN. Change the "VLAN Type" to "VLAN" and change the "VLAN ID" to a network allocated and dedicated to vMotion traffic exclusively.
References:
  • CCI-002418

STIG ID:
ESXI-65-000049		 Group ID:
V-100543		 Rule ID:
SV-109647r1_rule		 Severity:
CAT II
Requirement: The ESXi host must protect the confidentiality and integrity of transmitted information by protecting ESXi management traffic.
Discussion: The vSphere management network provides access to the vSphere management interface on each component. Services running on the management interface provide an opportunity for an attacker to gain privileged access to the systems. Any remote attack most likely would begin with gaining entry to this network.
Check: The Management VMkernel port group should in a dedicated VLAN that can be on a common standard or distributed virtual switch as long as the Management VLAN is not shared by any other function and it not accessible to anything other than management related functions such as vCenter. The check for this will be unique per environment.

From the vSphere Web Client select the ESXi host and go to Configure >> Networking and review the VLAN associated with the Management VMkernel and verify they are dedicated for that purpose and are logically separated from other functions.

If the network segment is accessible, except to networks where other management-related entities are located such as vCenter, this is a finding.
Fix: From the vSphere Web Client select the ESXi host and go to Configure >> Networking >> VMkernel adapters. Select the Management VMkernel and click Edit settings >> On the Port properties tab uncheck everything but "Management.” On the IP Settings tab >> Enter the appropriate IP address and subnet information and click OK. Set the appropriate VLAN ID >> Configure >> Networking >> Virtual switches. Select the Management portgroup and click Edit settings >> On the properties tab, enter the appropriate VLAN ID and click OK.
References:
  • CCI-002418

STIG ID:
ESXI-65-000050		 Group ID:
V-94047		 Rule ID:
SV-104133r1_rule		 Severity:
CAT II
Requirement: The ESXi host must protect the confidentiality and integrity of transmitted information by protecting IP based management traffic.
Discussion: Virtual machines might share virtual switches and VLANs with the IP-based storage configurations. IP-based storage includes vSAN, iSCSI and NFS. This configuration might expose IP-based storage traffic to unauthorized virtual machine users. IP-based storage frequently is not encrypted. It can be viewed by anyone with access to this network. To restrict unauthorized users from viewing the IP-based storage traffic, the IP-based storage network must be logically separated from the production traffic. Configuring the IP-based storage adaptors on separate VLANs or network segments from other VMkernels and Virtual Machines will limit unauthorized users from viewing the traffic.
Check: IP-Based storage (iSCSI, NFS, vSAN) VMkernel port groups must be in a dedicated VLAN that can be on a common standard or distributed virtual switch that is logically separated from other traffic types. The check for this will be unique per environment.

From the vSphere Web Client select the ESXi Host and go to Configure >> Networking >> VMkernel adapters and review the VLANs associated with any IP-Based storage VMkernels and verify they are dedicated for that purpose and are logically separated from other functions.

If any IP-Based storage networks are not isolated from other traffic types, this is a finding.

If IP-based storage is not used, this is not applicable.
Fix: Configuration of an IP-Based VMkernel will be unique to each environment but for example to modify the IP address and VLAN information to the correct network on a standard switch for an iSCSI VMkernel do the following:

From the vSphere Web Client select the ESXi host and go to Configure >> Networking >> VMkernel adapters. Select the Storage VMkernel (for vSAN only) and click Edit settings >> On the Port properties tab uncheck everything but "vSAN.” On the IP Settings tab >> Enter the appropriate IP address and subnet information and click OK.

Set the appropriate VLAN ID >> Configure >> Networking >> Virtual switches. Select the Storage portgroup (iSCSI, NFS, vSAN) and click Edit settings >> On the properties tab, enter the appropriate VLAN ID and click OK.
References:
  • CCI-002418

STIG ID:
ESXI-65-000052		 Group ID:
V-94051		 Rule ID:
SV-104137r1_rule		 Severity:
CAT III
Requirement: The ESXi host must protect the confidentiality and integrity of transmitted information by utilizing different TCP/IP stacks where possible.
Discussion: There are three different TCP/IP stacks by default available on ESXi now which are Default, Provisioning, and vMotion. To better protect and isolate sensitive network traffic within ESXi admins must configure each of these stacks. Additional custom TCP/IP stacks can be created if desired.
Check: From the vSphere Web Client select the ESXi Host and go to Configure >> Networking >> TCP/IP configuration. Review the default system TCP/IP stacks and verify they are configured with the appropriate IP address information.

If vMotion and Provisioning VMKernels are in use and are not utilizing their own TCP/IP stack, this is a finding.
Fix: From the vSphere Web Client select the ESXi Host and go to Configure >> Networking >> TCP/IP configuration >> Select a TCP/IP stack >> Click Edit >> Enter the appropriate site specific IP address information for the particular TCP/IP stack and click OK.
References:
  • CCI-002418

STIG ID:
ESXI-65-000053		 Group ID:
V-94053		 Rule ID:
SV-104139r1_rule		 Severity:
CAT II
Requirement: SNMP must be configured properly on the ESXi host.
Discussion: If SNMP is not being used, it must remain disabled. If it is being used, the proper trap destination must be configured. If SNMP is not properly configured, monitoring information can be sent to a malicious host that can then use this information to plan an attack.
Check: From a PowerCLI command prompt while connected to the ESXi host run the following command:

Get-VMHostSnmp | Select *

or

From a console or ssh session run the follow command:

esxcli system snmp get

If SNMP is not in use and is enabled, this is a finding.

If SNMP is enabled and read only communities is set to public, this is a finding.

If SNMP is enabled and is not using v3 targets, this is a finding.

Note: SNMP v3 targets can only be viewed and configured from the esxcli command.
Fix: To disable SNMP run the following command from a PowerCLI command prompt while connected to the ESXi Host:

Get-VMHostSnmp | Set-VMHostSnmp -Enabled $false

or

From a console or ssh session run the follow command:

esxcli system snmp set -e no

To configure SNMP for v3 targets use the "esxcli system snmp set" command set.
References:
  • CCI-000366

STIG ID:
ESXI-65-000054		 Group ID:
V-94055		 Rule ID:
SV-104141r1_rule		 Severity:
CAT III
Requirement: The ESXi host must enable bidirectional CHAP authentication for iSCSI traffic.
Discussion: When enabled, vSphere performs bidirectional authentication of both the iSCSI target and host. There is a potential for a MiTM attack, when not authenticating both the iSCSI target and host, in which an attacker might impersonate either side of the connection to steal data. Bidirectional authentication mitigates this risk.
Check: From the vSphere Web Client select the ESXi Host and go to Configure >> Storage >> Storage Adapters >> Select the iSCSI adapter >> Properties >> Authentication method and view the CHAP configuration and verify CHAP is "Required" for target and host authentication.

or

From a PowerCLI command prompt while connected to the ESXi host run the following command:

Get-VMHost | Get-VMHostHba | Where {$_.Type -eq "iscsi"} | Select AuthenticationProperties -ExpandProperty AuthenticationProperties

If iSCSI is not used, this is not a finding.

If iSCSI is used and CHAP is not set to "Required" for both the target and host, this is a finding.

If iSCSI is used and unique CHAP secrets are not used for each host, this is a finding.
Fix: From the vSphere Web Client select the ESXi Host and go to Configure >> Storage >> Storage Adapters >> Select the iSCSI adapter >> Properties >> Authentication and click the Edit button. Set Authentication method to “Use bidirectional CHAP” and enter a unique secret for each traffic flow direction.

or

From a PowerCLI command prompt while connected to the ESXi host run the following command:

Get-VMHost | Get-VMHostHba | Where {$_.Type -eq "iscsi"} | Set-VMHostHba -ChapType Required -ChapName "chapname" -ChapPassword "password" -MutualChapEnabled $true -MutualChapName "mutualchapname" -MutualChapPassword "mutualpassword"
References:
  • CCI-000366

STIG ID:
ESXI-65-000055		 Group ID:
V-94057		 Rule ID:
SV-104143r1_rule		 Severity:
CAT III
Requirement: The ESXi host must disable Inter-VM transparent page sharing.
Discussion: Published academic papers have demonstrated that by forcing a flush and reload of cache memory, it is possible to measure memory timings to try and determine an AES encryption key in use on another virtual machine running on the same physical processor of the host server if Transparent Page Sharing is enabled between the two virtual machines. This technique works only in a highly controlled system configured in a non-standard way that VMware believes would not be recreated in a production environment.

Even though VMware believes information being disclosed in real world conditions is unrealistic, out of an abundance of caution upcoming ESXi Update releases will no longer enable TPS between Virtual Machines by default (TPS will still be utilized within individual VMs).
Check: From the vSphere Web Client select the ESXi Host and go to Configure >> System >> Advanced System Settings. Select the Mem.ShareForceSalting value and verify it is set to 2.

or

From a PowerCLI command prompt while connected to the ESXi host run the following command:

Get-VMHost | Get-AdvancedSetting -Name Mem.ShareForceSalting

If the Mem.ShareForceSalting setting is not set to 2, this is a finding.
Fix: From the vSphere Web Client select the ESXi Host and go to Configure >> System >> Advanced System Settings. Click Edit and select the Mem.ShareForceSalting value and configure it to 2.

or

From a PowerCLI command prompt while connected to the ESXi host run the following commands:

Get-VMHost | Get-AdvancedSetting -Name Mem.ShareForceSalting | Set-AdvancedSetting -Value 2
References:
  • CCI-000366

STIG ID:
ESXI-65-000056		 Group ID:
V-94059		 Rule ID:
SV-104145r1_rule		 Severity:
CAT II
Requirement: The ESXi host must configure the firewall to restrict access to services running on the host.
Discussion: Unrestricted access to services running on an ESXi host can expose a host to outside attacks and unauthorized access. Reduce the risk by configuring the ESXi firewall to only allow access from authorized networks.
Check: From the vSphere Web Client select the ESXi Host and go to Configure >> System >> Security Profile. Under the Firewall section click Edit and for each enabled service click Firewall and review the allowed IPs. Check this for Incoming and Outgoing connections.

or

From a PowerCLI command prompt while connected to the ESXi host run the following command:

Get-VMHost | Get-VMHostFirewallException | Where {$_.Enabled -eq $true} | Select Name,Enabled,@{N="AllIPEnabled";E={$_.ExtensionData.AllowedHosts.AllIP}}

If for an enabled service "Allow connections from any IP address" is selected, this is a finding.
Fix: From the vSphere Web Client select the ESXi Host and go to Configure >> System >> Security Profile. Under the Firewall section click Edit and for each enabled service uncheck the check box to “Allow connections from any IP address,” and input the site specific network(s) required.Configure this for Incoming and Outgoing connections.

or

From a PowerCLI command prompt while connected to the ESXi host run the following command:

$esxcli = Get-EsxCli
#This disables the allow all rule for the target service
$esxcli.network.firewall.ruleset.set($false,$true,"sshServer")
$esxcli.network.firewall.ruleset.allowedip.add("192.168.0.0/24","sshServer")

This must be done for each enabled service.
References:
  • CCI-000366

STIG ID:
ESXI-65-000057		 Group ID:
V-94061		 Rule ID:
SV-104147r1_rule		 Severity:
CAT II
Requirement: The ESXi host must configure the firewall to block network traffic by default.
Discussion: In addition to service specific firewall rules ESXi has a default firewall rule policy to allow or deny incoming and outgoing traffic. Reduce the risk of attack by making sure this is set to deny incoming and outgoing traffic.
Check: From a PowerCLI command prompt while connected to the ESXi host run the following command:

Get-VMHostFirewallDefaultPolicy

If the Incoming or Outgoing policies are True, this is a finding.
Fix: From a PowerCLI command prompt while connected to the ESXi host run the following command:

Get-VMHostFirewallDefaultPolicy | Set-VMHostFirewallDefaultPolicy -AllowIncoming $false -AllowOutgoing $false
References:
  • CCI-000366

STIG ID:
ESXI-65-000058		 Group ID:
V-94063		 Rule ID:
SV-104149r1_rule		 Severity:
CAT III
Requirement: The ESXi host must enable BPDU filter on the host to prevent being locked out of physical switch ports with Portfast and BPDU Guard enabled.
Discussion: BPDU Guard and Portfast are commonly enabled on the physical switch to which the ESXi host is directly connected to reduce the STP convergence delay. If a BPDU packet is sent from a virtual machine on the ESXi host to the physical switch so configured, a cascading lockout of all the uplink interfaces from the ESXi host can occur. To prevent this type of lockout, BPDU Filter can be enabled on the ESXi host to drop any BPDU packets being sent to the physical switch. The caveat is that certain SSL VPN which use Windows bridging capability can legitimately generate BPDU packets. The administrator should verify that there are no legitimate BPDU packets generated by virtual machines on the ESXi host prior to enabling BPDU Filter. If BPDU Filter is enabled in this situation, enabling Reject Forged Transmits on the virtual switch port group adds protection against Spanning Tree loops.
Check: From the vSphere Web Client select the ESXi Host and go to Configure >> System >> Advanced System Settings. Select the Net.BlockGuestBPDU value and verify it is set to 1.

or

From a PowerCLI command prompt while connected to the ESXi host run the following command:

Get-VMHost | Get-AdvancedSetting -Name Net.BlockGuestBPDU

If the Net.BlockGuestBPDU setting is not set to 1, this is a finding.
Fix: From the vSphere Web Client select the ESXi Host and go to Configure >> System >> Advanced System Settings. Click Edit and select the Net.BlockGuestBPDU value and configure it to 1.

or

From a PowerCLI command prompt while connected to the ESXi host run the following commands:

Get-VMHost | Get-AdvancedSetting -Name Net.BlockGuestBPDU | Set-AdvancedSetting -Value 1
References:
  • CCI-000366

STIG ID:
ESXI-65-000059		 Group ID:
V-94065		 Rule ID:
SV-104151r1_rule		 Severity:
CAT II
Requirement: The virtual switch Forged Transmits policy must be set to reject on the ESXi host.
Discussion: If the virtual machine operating system changes the MAC address, the operating system can send frames with an impersonated source MAC address at any time. This allows an operating system to stage malicious attacks on the devices in a network by impersonating a network adaptor authorized by the receiving network.

This means the virtual switch does not compare the source and effective MAC addresses.

To protect against MAC address impersonation, all virtual switches should have forged transmissions set to Reject. Reject Forged Transmit can be set at the vSwitch and/or the Portgroup level. You can override switch level settings at the Portgroup level.
Check: From the vSphere Web Client go to Configure >> Networking >> Virtual Switches. View the properties on each virtual switch and port group and verify "Forged Transmits" is set to reject.

or

From a PowerCLI command prompt while connected to the ESXi host run the following commands:

Get-VirtualSwitch | Get-SecurityPolicy
Get-VirtualPortGroup | Get-SecurityPolicy

If the "Forged Transmits" policy is set to accept, this is a finding.
Fix: From the vSphere Web Client go to Configure >> Networking >> Virtual Switches. For each virtual switch and port group click Edit settings and change "Forged Transmits" to reject.

or

From a PowerCLI command prompt while connected to the ESXi host run the following commands:

Get-VirtualSwitch | Get-SecurityPolicy | Set-SecurityPolicy -ForgedTransmits $false
Get-VirtualPortGroup | Get-SecurityPolicy | Set-SecurityPolicy -ForgedTransmitsInherited $true
References:
  • CCI-000366

STIG ID:
ESXI-65-000060		 Group ID:
V-94067		 Rule ID:
SV-104153r1_rule		 Severity:
CAT I
Requirement: The virtual switch MAC Address Change policy must be set to reject on the ESXi host.
Discussion: If the virtual machine operating system changes the MAC address, it can send frames with an impersonated source MAC address at any time. This allows it to stage malicious attacks on the devices in a network by impersonating a network adaptor authorized by the receiving network. This will prevent VMs from changing their effective MAC address. It will affect applications that require this functionality. This will also affect how a layer 2 bridge will operate. This will also affect applications that require a specific MAC address for licensing. Reject MAC Changes can be set at the vSwitch and/or the Portgroup level. You can override switch level settings at the Portgroup level.
Check: From the vSphere Web Client go to Configure >> Networking >> Virtual Switches. View the properties on each virtual switch and port group and verify "MAC Address Changes" is set to reject.

or

From a PowerCLI command prompt while connected to the ESXi host run the following commands:

Get-VirtualSwitch | Get-SecurityPolicy
Get-VirtualPortGroup | Get-SecurityPolicy

If the "MAC Address Changes" policy is set to accept, this is a finding.
Fix: From the vSphere Web Client go to Configure >> Networking >> Virtual Switches. For each virtual switch and port group click Edit settings and change "MAC Address Changes" to reject.

or

From a PowerCLI command prompt while connected to the ESXi host run the following commands:

Get-VirtualSwitch | Get-SecurityPolicy | Set-SecurityPolicy -MacChanges $false
Get-VirtualPortGroup | Get-SecurityPolicy | Set-SecurityPolicy -MacChangesInherited $true
References:
  • CCI-000366

STIG ID:
ESXI-65-000061		 Group ID:
V-94069		 Rule ID:
SV-104155r1_rule		 Severity:
CAT II
Requirement: The virtual switch Promiscuous Mode policy must be set to reject on the ESXi host.
Discussion: When promiscuous mode is enabled for a virtual switch all virtual machines connected to the Portgroup have the potential of reading all packets across that network, meaning only the virtual machines connected to that Portgroup. Promiscuous mode is disabled by default on the ESXi Server, and this is the recommended setting. Promiscous mode can be set at the vSwitch and/or the Portgroup level. You can override switch level settings at the Portgroup level.
Check: From the vSphere Web Client go to Configure >> Networking >> Virtual Switches. View the properties on each virtual switch and port group and verify "Promiscuous Mode" is set to reject.

or

From a PowerCLI command prompt while connected to the ESXi host run the following commands:

Get-VirtualSwitch | Get-SecurityPolicy
Get-VirtualPortGroup | Get-SecurityPolicy

If the "Promiscuous Mode" policy is set to accept, this is a finding.
Fix: From the vSphere Web Client go to Configure >> Networking >> Virtual Switches. For each virtual switch and port group click Edit settings and change "Promiscuous Mode" to reject.

or

From a PowerCLI command prompt while connected to the ESXi host run the following commands:

Get-VirtualSwitch | Get-SecurityPolicy | Set-SecurityPolicy -AllowPromiscuous $false
Get-VirtualPortGroup | Get-SecurityPolicy | Set-SecurityPolicy -AllowPromiscuousInherited $true
References:
  • CCI-000366

STIG ID:
ESXI-65-000062		 Group ID:
V-94071		 Rule ID:
SV-104157r1_rule		 Severity:
CAT II
Requirement: The ESXi host must prevent unintended use of the dvFilter network APIs.
Discussion: If you are not using products that make use of the dvfilter network API, the host should not be configured to send network information to a VM. If the API is enabled an attacker might attempt to connect a VM to it thereby potentially providing access to the network of other VMs on the host. If you are using a product that makes use of this API then verify that the host has been configured correctly. If you are not using such a product make sure the setting is blank.
Check: From the vSphere Web Client select the ESXi Host and go to Configure >> System >> Advanced System Settings. Select the Net.DVFilterBindIpAddress value and verify the value is blank or the correct IP address of a security appliance if in use.

or

From a PowerCLI command prompt while connected to the ESXi host run the following command:

Get-VMHost | Get-AdvancedSetting -Name Net.DVFilterBindIpAddress

If the Net.DVFilterBindIpAddress is not blank and security appliances are not in use on the host, this is a finding.
Fix: From the vSphere Web Client select the ESXi Host and go to Configure >> System >> Advanced System Settings. Click Edit and select the Net.DVFilterBindIpAddress value and remove any incorrect addresses.

or

From a PowerCLI command prompt while connected to the ESXi host run the following command:

Get-VMHost | Get-AdvancedSetting -Name Net.DVFilterBindIpAddress | Set-AdvancedSetting -Value ""
References:
  • CCI-000366

STIG ID:
ESXI-65-000063		 Group ID:
V-94073		 Rule ID:
SV-104159r1_rule		 Severity:
CAT II
Requirement: For the ESXi host all port groups must be configured to a value other than that of the native VLAN.
Discussion: ESXi does not use the concept of native VLAN. Frames with VLAN specified in the port group will have a tag, but frames with VLAN not specified in the port group are not tagged and therefore will end up as belonging to native VLAN of the physical switch. For example, frames on VLAN 1 from a Cisco physical switch will be untagged, because this is considered as the native VLAN. However, frames from ESXi specified as VLAN 1 will be tagged with a "1"; therefore, traffic from ESXi that is destined for the native VLAN will not be correctly routed (because it is tagged with a "1" instead of being untagged), and traffic from the physical switch coming from the native VLAN will not be visible (because it is not tagged). If the ESXi virtual switch port group uses the native VLAN ID, traffic from those VMs will not be visible to the native VLAN on the switch, because the switch is expecting untagged traffic.
Check: From the vSphere Web Client select the ESXi Host and go to Configure >> Networking >> Virtual switches. For each virtual switch, review the port group VLAN tags and verify they are not set to the native VLAN ID of the attached physical switch.

or

From a PowerCLI command prompt while connected to the ESXi host run the following command:

Get-VirtualPortGroup | Select Name, VLanId

If any port group is configured with the native VLAN of the ESXi hosts attached physical switch, this is a finding.
Fix: From the vSphere Web Client select the ESXi Host and go to Configure >> Networking >> Virtual switches. Highlight a port group (where VLAN ID set to native VLAN ID) and click Edit settings. Change the VLAN ID to a non-native VLAN and click OK.

or

From a PowerCLI command prompt while connected to the ESXi host run the following command:

Get-VirtualPortGroup -Name "portgroup name" | Set-VirtualPortGroup -VLanId "New VLAN#"
References:
  • CCI-000366

STIG ID:
ESXI-65-000064		 Group ID:
V-94075		 Rule ID:
SV-104161r1_rule		 Severity:
CAT II
Requirement: For the ESXi host all port groups must not be configured to VLAN 4095 unless Virtual Guest Tagging (VGT) is required.
Discussion: When a port group is set to VLAN 4095, this activates VGT mode. In this mode, the vSwitch passes all network frames to the guest VM without modifying the VLAN tags, leaving it up to the guest to deal with them. VLAN 4095 should be used only if the guest has been specifically configured to manage VLAN tags itself. If VGT is enabled inappropriately, it might cause denial-of-service or allow a guest VM to interact with traffic on an unauthorized VLAN.
Check: From the vSphere Web Client select the ESXi Host and go to Configure >> Networking >> Virtual switches. For each virtual switch, review the port group VLAN tags and verify they are not set to 4095.

or

From a PowerCLI command prompt while connected to the ESXi host run the following command:

Get-VirtualPortGroup | Select Name, VLanID

If any port group is configured with VLAN 4095 and is not documented as a needed exception, this is a finding.
Fix: From the vSphere Web Client select the ESXi Host and go to Configure >> Networking >> Virtual switches. Highlight a port group (where VLAN ID set to 4095) and click Edit settings. Change the VLAN ID to not be 4095 and click OK.

or

From a PowerCLI command prompt while connected to the ESXi host run the following command:

Get-VirtualPortGroup -Name "portgroup name" | Set-VirtualPortGroup -VLanId "New VLAN#"
References:
  • CCI-000366

STIG ID:
ESXI-65-000065		 Group ID:
V-94077		 Rule ID:
SV-104163r1_rule		 Severity:
CAT II
Requirement: For the ESXi host all port groups must not be configured to VLAN values reserved by upstream physical switches.
Discussion: Certain physical switches reserve certain VLAN IDs for internal purposes and often disallow traffic configured to these values. For example, Cisco Catalyst switches typically reserve VLANs 1001–1024 and 4094, while Nexus switches typically reserve 3968–4047 and 4094. Check with the documentation for your specific switch. Using a reserved VLAN might result in a denial of service on the network.
Check: From the vSphere Web Client select the ESXi Host and go to Configure >> Networking >> Virtual switches. For each virtual switch, review the port group VLAN tags and verify they are not set to a reserved VLAN ID.

or

From a PowerCLI command prompt while connected to the ESXi host run the following command:

Get-VirtualPortGroup | Select Name, VLanId

If any port group is configured with a reserved VLAN ID, this is a finding.
Fix: From the vSphere Web Client select the ESXi Host and go to Configure >> Networking >> Virtual switches. Highlight a port group (where VLAN ID set to 4095) and click Edit settings (pencil). Change the VLAN ID to not be a reserved VLAN ID and click OK.

or

From a PowerCLI command prompt while connected to the ESXi host run the following command:

Get-VirtualPortGroup -Name "portgroup name" | Set-VirtualPortGroup -VLanId "New VLAN#"
References:
  • CCI-000366

STIG ID:
ESXI-65-000066		 Group ID:
V-94079		 Rule ID:
SV-104165r1_rule		 Severity:
CAT II
Requirement: For physical switch ports connected to the ESXi host, the non-negotiate option must be configured for trunk links between external physical switches and virtual switches in VST mode.
Discussion: In order to communicate with virtual switches in VST mode, external switch ports must be configured as trunk ports. VST mode does not support Dynamic Trunking Protocol (DTP), so the trunk must be static and unconditional. The auto or desirable physical switch settings do not work with the ESXi Server because the physical switch communicates with the ESXi Server using DTP. The non-negotiate and on options unconditionally enable VLAN trunking on the physical switch and create a VLAN trunk link between the ESXi Server and the physical switch. The difference between non-negotiate and on options is that on mode still sends out DTP frames, whereas the non-negotiate option does not. The non-negotiate option should be used for all VLAN trunks, to minimize unnecessary network traffic for virtual switches in VST mode.
Check: Note that this check refers to an entity outside the physical scope of the ESXi server system. The configuration of external switch ports as trunk ports must be documented. Virtual Switch Tagging (VST) mode does not support Dynamic Trunking Protocol (DTP), so the trunk must be static and unconditional. Inspect the documentation and verify that the documentation is correct and updated on an organization defined frequency and/or whenever modifications are made to either ESXi hosts or the upstream external switch ports.

If DTP is enabled on the physical switch ports connected to the ESXi Host, this is a finding.
Fix: Note that this check refers to an entity outside the physical scope of the ESXi server system. Document the configuration of external switch ports as trunk ports. Log in to the vendor-specific physical switch and disable DTP on the physical switch ports connected to the ESXi Host. Update the documentation on an organization defined frequency or whenever modifications are made to either ESXi hosts or the upstream external switch ports.
References:
  • CCI-000366

STIG ID:
ESXI-65-000067		 Group ID:
V-94081		 Rule ID:
SV-104167r1_rule		 Severity:
CAT III
Requirement: All ESXi host-connected physical switch ports must be configured with spanning tree disabled.
Discussion: Since VMware virtual switches do not support STP, the ESXi host-connected physical switch ports must have portfast configured if spanning tree is enabled to avoid loops within the physical switch network. If these are not set, potential performance and connectivity issues might arise.
Check: Note that this check refers to an entity outside the physical scope of the ESXi server system. The configuration of upstream physical switches must be documented to ensure that spanning tree protocol is disabled and/or portfast is configured for all physical ports connected to ESXi hosts. Inspect the documentation and verify that the documentation is updated on an organization defined frequency and/or whenever modifications are made to either ESXi hosts or the upstream physical switches. Alternatively, log in to the physical switch and verify that spanning tree protocol is disabled and/or portfast is configured for all physical ports connected to ESXi hosts.

If the physical switch's spanning tree protocol is not disabled or portfast is not configured for all physical ports connected to ESXi hosts, this is a finding.
Fix: Note that this check refers to an entity outside the scope of the ESXi server system. Document the upstream physical switch configuration for spanning tree protocol disablement and/or portfast configuration for all physical ports connected to ESXi hosts. Log in to the physical switch(es) and disable spanning tree protocol and/or configure portfast for all physical ports connected to ESXi hosts. Update the documentation on an organization defined frequency or whenever modifications are made to either ESXi hosts or the upstream physical switches.
References:
  • CCI-000366

STIG ID:
ESXI-65-000068		 Group ID:
V-94083		 Rule ID:
SV-104169r1_rule		 Severity:
CAT II
Requirement: All ESXi host-connected virtual switch VLANs must be fully documented and have only the required VLANs.
Discussion: When defining a physical switch port for trunk mode, only specified VLANs must be configured on the VLAN trunk link. The risk with not fully documenting all VLANs on the vSwitch is that it is possible that a physical trunk port might be configured without needed VLANs, or with unneeded VLANs, potentially enabling an administrator to either accidentally or maliciously connect a VM to an unauthorized VLAN.
Check: Note that this check refers to an entity outside the physical scope of the ESXi server system. The configuration of upstream physical switches must be documented to ensure that unneeded VLANs are configured for all physical ports connected to ESXi hosts. Inspect the documentation and verify that the documentation is updated on an organization defined frequency and/or whenever modifications are made to either ESXi hosts or the upstream physical switches. Alternatively, log in to the physical switch and verify that only needed VLANs are configured for all physical ports connected to ESXi hosts.

If the physical switch's configuration is trunked VLANs that are not used by ESXi for all physical ports connected to ESXi hosts, this is a finding.
Fix: Note that this check refers to an entity outside the scope of the ESXi server system.

Remove any VLANs trunked across physical ports connected to ESXi hosts that are not in use.
References:
  • CCI-000366

STIG ID:
ESXI-65-000070		 Group ID:
V-94349		 Rule ID:
SV-104303r2_rule		 Severity:
CAT II
Requirement: The ESXi host must not provide root/administrator level access to CIM-based hardware monitoring tools or other third-party applications.
Discussion: The CIM system provides an interface that enables hardware-level management from remote applications via a set of standard APIs. Create a limited-privilege, read-only service account for CIM. Grant this role to the user on the ESXi server. Place this user in the Exception Users list. When/where write access is required, create/enable a limited-privilege, service account and grant only the minimum required privileges.
Check: The CIM system provides an interface that enables hardware-level management from remote applications via a set of standard APIs. Create a limited-privilege, read-only service account for CIM. Grant this role to the user on the ESXi server. Place this user in the Exception Users list. When/where write access is required, create/enable a limited-privilege, service account and grant only the minimum required privileges.

From the Host Client, select the ESXi host, right click and go to "Permissions". Verify the CIM account user role is limited to read only and CIM permissions.

If there is no dedicated CIM account and the root is used for CIM monitoring, this is a finding.

If write access is not required and the access level is not "read-only", this is a finding.
Fix: Create a role for the CIM account.

From the Host Client, go to manage, then Security & Users. Select Roles then click Add Role. Provide a name for the new role then select Host >> Cim >> Ciminteraction and click Add.

Add a CIM user account.

From the Host Client, go to manage, then Security & Users. Select Users then click Add User. Provide a name, description, and password for the new user then click Add.

Assign the CIM account permissions to the host with the new role.

From the Host Client, select the ESXi host, right click and go to "Permissions". Click Add User and select the CIM account from the drop down list and select the new CIM role from the drop down list and click Add User.
References:
  • CCI-000366

STIG ID:
ESXI-65-000071		 Group ID:
V-94477		 Rule ID:
SV-104307r1_rule		 Severity:
CAT I
Requirement: The ESXi host must verify the integrity of the installation media before installing ESXi.
Discussion: Always check the SHA1 or MD5 hash after downloading an ISO, offline bundle, or patch to ensure integrity and authenticity of the downloaded files.
Check: The downloaded ISO, offline bundle, or patch hash must be verified against the vendor's checksum to ensure the integrity and authenticity of the files.

See some typical command line example(s) for both the md5 and sha1 hash check(s) directly below.

# md5sum <filename>.iso
# sha1sum <filename>.iso

If any of the system's downloaded ISO, offline bundle, or system patch hashes cannot be verified against the vendor's checksum, this is a finding.
Fix: If the hash returned from the md5sum or sha1sum commands do not match the vendor's hash, the downloaded software must be discarded.

If the physical media is obtained from VMware and the security seal is broken, the software must be returned to VMware for replacement.
References:
  • CCI-000366

STIG ID:
ESXI-65-000072		 Group ID:
V-94479		 Rule ID:
SV-104309r1_rule		 Severity:
CAT I
Requirement: The ESXi host must have all security patches and updates installed.
Discussion: Installing software updates is a fundamental mitigation against the exploitation of publicly-known vulnerabilities.
Check: If vCenter Update Manager is used on the network it can be used to scan all hosts for missing patches. From the vSphere Client go to Hosts and Clusters > Update Manager tab and select scan to view all hosts compliance status.

If vCenter Update Manager is not used a hosts compliance status must be manually determined by the build number. The following VMware KB 1014508 can be used to correlate patches with build numbers.

If the ESXi host does not have the latest patches, this is a finding.

If the ESXi host is not on a supported release, this is a finding.

VMware also publishes Advisories on security patches, and offers a way to subscribe to email alerts for them.
https://www.vmware.com/support/policies/security_response
Fix: If vCenter Update Manager is used on the network, hosts can be remediated from the vSphere Web Client. From the vSphere Web Client go to Hosts and Clusters >> Update Manager tab and select a non-compliant host and click the Remediate button.

To manually remediate a host the patch file must be copied locally and the following command run from an SSH session connected to the ESXi host, or from the ESXi shell:

esxcli software vib update -d <path to offline patch bundle.zip>
References:
  • CCI-000366

STIG ID:
ESXI-65-000076		 Group ID:
V-94487		 Rule ID:
SV-104317r1_rule		 Severity:
CAT II
Requirement: The ESXi host must enable Secure Boot.
Discussion: Secure Boot is a protocol of UEFI firmware that ensures the integrity of the boot process from hardware up through to the OS. Secure Boot for ESXi requires support from the firmware and it requires that all ESXi kernel modules, drivers, and VIBs be signed by VMware or a partner subordinate.
Check: Temporarily enable SSH, connect to the ESXi host and run the following command:

/usr/lib/vmware/secureboot/bin/secureBoot.py -s

If the output is not Enabled, this is a finding.
Fix: Temporarily enable SSH, connect to the ESXi host and run the following command:

/usr/lib/vmware/secureboot/bin/secureBoot.py -c

If the output indicates that Secure Boot cannot be enabled, correct the discrepancies and try again. If the discrepancies cannot be rectified this finding is downgraded to a CAT III.

Consult your vendor documentation and boot the host into BIOS setup mode. Enable UEFI boot mode and Secure Boot. Restart the host.

Temporarily enable SSH, connect to the ESXi host and run the following command to verify that Secure Boot is enabled:

/usr/lib/vmware/secureboot/bin/secureBoot.py -s
References:
  • CCI-000366

STIG ID:
ESXI-65-000078		 Group ID:
V-94489		 Rule ID:
SV-104319r1_rule		 Severity:
CAT II
Requirement: The ESXi host must use DoD-approved certificates.
Discussion: The default self-signed, VMCA issued host certificate must be replaced with a DoD-approved certificate. The use of a DoD certificate on the host assures clients that the service they are connecting to is legitimate and properly secured.
Check: Temporarily enable SSH, connect to the ESXi host and run the following command:

# openssl x509 -in /etc/vmware/ssl/rui.crt -text | grep Issuer

If the issuer is not a DoD approved certificate authority, this is a finding.
Fix: Obtain a DoD issued certificate and private key for the host following the below requirements:

Key size: 2048 bits or more (PEM encoded)
Key format: PEM. VMware supports PKCS8 and PKCS1 (RSA keys)
x509 version 3
SubjectAltName must contain DNS Name=<machine_FQDN>
CRT (Base-64) format
Contains the following Key Usages: Digital Signature, Non Repudiation, Key Encipherment
Start time of one day before the current time
CN (and SubjectAltName) set to the host name (or IP address) that the ESXi host has in the vCenter Server inventory.

Put the host into maintenance mode.

Temporarily enable SSH on the host. SCP the new certificate and key to /tmp. SSH to the host. Back up the existing certificate and key:

mv /etc/vmware/ssl/rui.crt /etc/vmware/ssl/rui.crt.bak
mv /etc/vmware/ssl/rui.key /etc/vmware/ssl/rui.key.bak

Copy your new certificate and key to /etc/vmware/ssl/ and rename them to rui.crt and rui.key respectively. Restart management agents to implement the new certificate:

services.sh restart

From the vSphere Web Client go to vCenter Inventory Lists >> vCenter Servers >> Select your vCenter Server >> Manage >> Settings >> Advanced Settings. Find or create the vpxd.certmgmt.mode key and set its value to custom.
References:
  • CCI-000366

STIG ID:
ESXI-65-100037		 Group ID:
V-94505		 Rule ID:
SV-104335r2_rule		 Severity:
CAT III
Requirement: The ESXi host must require individuals to be authenticated with an individual authenticator prior to using a group authenticator by using Active Directory for local user authentication.
Discussion: Join ESXi hosts to an Active Directory (AD) domain to eliminate the need to create and maintain multiple local user accounts. Using AD for user authentication simplifies the ESXi host configuration, ensures password complexity and reuse policies are enforced and reduces the risk of security breaches and unauthorized access. Note: If the AD group "ESX Admins" (default) exists then all users and groups that are assigned as members to this group will have full administrative access to all ESXi hosts the domain.
Check: For systems that do not use Active Directory and have no local user accounts, other than "root" and/or "vpxuser", this is not applicable.

From the vSphere Client select the ESXi host and go to Configuration >> Authentication Services. Verify the "Directory Services Type" is set to "Active Directory".

or

From a PowerCLI command prompt while connected to the ESXi host run the following command:

Get-VMHost | Get-VMHostAuthentication

For systems that do not use Active Directory and do have local user accounts, other than "root" and/or "vpxuser"", this is a finding.

If the "Directory Services Type" is not set to "Active Directory", this is a finding.
If you are not using Host Profiles to join active directory, this is not a finding.
Fix: From the vSphere Client select the ESXi host and go to Configuration >> Authentication Services. Click "Properties" and change the "Directory Service Type" to "Active Directory", enter the domain to join, check "Use vSphere Authentication Proxy" and enter the proxy server address then click "Join Domain".

or

From a PowerCLI command prompt while connected to the ESXi host run the following command:

Get-VMHost | Get-VMHostAuthentication | Set-VMHostAuthentication -JoinDomain -Domain "domain name" -User "username" -Password "password"
References:
  • CCI-000770

UNCLASSIFIED