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VMware vSphere 7.0 ESXi Security Technical Implementation Guide

Overview

Version Date Finding Count (75) Downloads
1 2024-12-16 CAT I (High): 4 CAT II (Medium): 65 CAT III (Low): 6 Excel JSON XML
Stig Description
This Security Technical Implementation Guide is published as a tool to improve the security of Department of Defense (DOD) information systems. The requirements are derived from the National Institute of Standards and Technology (NIST) 800-53 and related documents. Comments or proposed revisions to this document should be sent via email to the following address: disa.stig_spt@mail.mil.
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I - Mission Critical Classified I - Mission Critical Public I - Mission Critical Sensitive II - Mission Critical Classified II - Mission Critical Public II - Mission Critical Sensitive III - Mission Critical Classified III - Mission Critical Public III - Mission Critical Sensitive

Findings - MAC I - Mission Critical Public

Finding ID Severity Title Description
V-256429 High The ESXi host must exclusively enable Transport Layer Security (TLS) 1.2 for all endpoints. TLS 1.0 and 1.1 are deprecated protocols with well-published shortcomings and vulnerabilities. TLS 1.2 should be enabled on all interfaces and SSLv3, TL 1.1, and 1.0 disabled, where supported. Mandating TLS 1.2 may break third-party integrations and add-ons to vSphere. Test these integrations carefully after implementing TLS 1.2 and roll...
V-256428 High The ESXi host must have all security patches and updates installed. Installing software updates is a fundamental mitigation against the exploitation of publicly known vulnerabilities.
V-256421 High All port groups on standard switches must be configured to reject guest Media Access Control (MAC) address changes. If the virtual machine (VM) 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...
V-256410 High The ESXi Image Profile and vSphere Installation Bundle (VIB) acceptance levels must be verified. 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...
V-256449 Medium The ESXi host SSH daemon must be configured to only use FIPS 140-2 validated ciphers. Use of weak or untested encryption algorithms undermines the purposes of using encryption to protect data. ESXi must implement cryptographic modules adhering to the higher standards approved by the federal government because this provides assurance they have been tested and validated.
V-256448 Medium The ESXi Common Information Model (CIM) service must be disabled. The CIM system provides an interface that enables hardware-level management from remote applications via a set of standard application programming interfaces (APIs). These APIs are consumed by external applications such as HP SIM or Dell OpenManage for agentless, remote hardware monitoring of the ESXi host. To reduce attack surface area...
V-256447 Medium The ESXi host must implement Secure Boot enforcement. Secure Boot is part of the UEFI firmware standard. With UEFI Secure Boot enabled, a host refuses to load any UEFI driver or app unless the operating system bootloader has a valid digital signature. Secure Boot for ESXi requires support from the firmware and it requires that all ESXi kernel...
V-256446 Medium The ESXi host must require TPM-based configuration encryption. An ESXi host's configuration consists of configuration files for each service that runs on the host. The configuration files typically reside in the /etc/ directory, but they can also reside in other namespaces. The configuration files contain run-time information about the state of the services. Over time, the default values...
V-256445 Medium The ESXi host must not be configured to override virtual machine (VM) logger settings. Each VM on an ESXi host runs in its own "vmx" process. Upon creation, a vmx process will look in two locations for configuration items, the ESXi host itself and the per-vm *.vmx file in the VM storage path on the datastore. The settings on the ESXi host are read...
V-256444 Medium The ESXi host must not be configured to override virtual machine (VM) configurations. Each VM on an ESXi host runs in its own "vmx" process. Upon creation, a vmx process will look in two locations for configuration items, the ESXi host itself and the per-vm *.vmx file in the VM storage path on the datastore. The settings on the ESXi host are read...
V-256443 Medium The ESXi host must be configured with an appropriate maximum password age. The older an ESXi local account password is, the larger the opportunity window is for attackers to guess, crack or reuse a previously cracked password. Rotating passwords on a regular basis is a fundamental security practice and one that ESXi supports.
V-256442 Medium The ESXi host rhttpproxy daemon must use FIPS 140-2 validated cryptographic modules to protect the confidentiality of remote access sessions. ESXi runs a reverse proxy service called rhttpproxy that front ends internal services and application programming interfaces (APIs) over one HTTPS port by redirecting virtual paths to localhost ports. This proxy implements a FIPS 140-2 validated OpenSSL cryptographic module that is in FIPS mode by default. This configuration must be...
V-256441 Medium The ESXi Host Client must be configured with a session timeout.
V-256440 Medium The ESXi host must configure a session timeout for the vSphere API. The vSphere API (VIM) allows for remote, programmatic administration of the ESXi host. Authenticated API sessions are no different from a risk perspective than authenticated UI sessions and they need similar protections. One of these protections is a basic inactivity timeout, after which the session will be invalidated and reauthentication...
V-256439 Medium The ESXi host must enable volatile key destruction. By default, pages allocated for virtual machines (VMs), userspace applications, and kernel threads are zeroed out at allocation time. ESXi will always ensure that no nonzero pages are exposed to VMs or userspace applications. While this prevents exposing cryptographic keys from VMs or userworlds to other clients, these keys can...
V-256438 Medium The ESXi host must verify certificates for SSL syslog endpoints. When sending syslog data to a remote host, ESXi can be configured to use any combination of TCP, UDP and SSL transports. When using SSL, the server certificate must be validated to ensure that the host is connecting to a valid syslog server.
V-256437 Medium The ESXi host must enable strict x509 verification for SSL syslog endpoints. When sending syslog data to a remote host via SSL, the ESXi host is presented with the endpoint's SSL server certificate. In addition to trust verification, configured elsewhere, this "x509-strict" option performs additional validity checks on CA root certificates during verification. These checks are generally not performed (CA roots are...
V-256436 Medium The ESXi host must enable audit logging. ESXi offers both local and remote audit recordkeeping to meet the requirements of the NIAP Virtualization Protection Profile and Server Virtualization Extended Package. Local records are stored on any accessible local or VMFS path. Remote records are sent to the global syslog servers configured elsewhere. To operate in the NIAP...
V-256435 Medium The ESXi host OpenSLP service must be disabled. OpenSLP implements the Service Location Protocol to help CIM clients discover CIM servers over TCP 427. This service is not widely needed and has had vulnerabilities exposed in the past. To reduce attack surface area and following the minimum functionality principal, the OpenSLP service must be disabled unless explicitly needed...
V-256434 Medium The ESXi host Secure Shell (SSH) daemon must disable port forwarding. While enabling Transmission Control Protocol (TCP) tunnels is a valuable function of sshd, this feature is not appropriate for use on the ESXi hypervisor.
V-256433 Medium The ESXi host must not suppress warnings about unmitigated hyperthreading vulnerabilities. The L1 Terminal Fault (L1TF) CPU vulnerabilities published in 2018 have patches and mitigations available in vSphere. However, there are performance impacts to these mitigations that require careful thought and planning from the system administrator before implementation. Until a mitigation is implemented, the UI warning about the lack of a...
V-256432 Medium The ESXi host must not suppress warnings that the local or remote shell sessions are enabled. Warnings that local or remote shell sessions are enabled alert administrators to activity they may not be aware of and need to investigate.
V-256431 Medium The ESXi host must use DOD-approved certificates. The default self-signed host certificate issued by the VMware Certificate Authority (VMCA) must be replaced with a DOD-approved certificate when the host will be accessed directly, such as during a virtual machine (VM) console connection. The use of a DOD certificate on the host assures clients the service they are...
V-256430 Medium The ESXi host must enable Secure Boot. Secure Boot is part of the Unified Extensible Firmware Interface (UEFI) firmware standard. With UEFI Secure Boot enabled, a host refuses to load any UEFI driver or app unless the operating system bootloader has a valid digital signature. Secure Boot for ESXi requires support from the firmware and requires that...
V-256427 Medium The ESXi host must not provide root/administrator-level access to Common Information Model (CIM)-based hardware monitoring tools or other third-party applications. The CIM system provides an interface that enables hardware-level management from remote applications via a set of standard application programming interfaces (APIs). In environments that implement CIM hardware monitoring, create a limited-privilege, read-only service account for CIM and place this user in the Exception Users list. When CIM write access...
V-256426 Medium All port groups on standard switches must not be configured to virtual local area network (VLAN) values reserved by upstream physical switches. 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 to 1024 and 4094, while Nexus switches typically reserve 3968 to 4094. Check the documentation for the specific switch in use. Using a...
V-256425 Medium All port groups on standard switches must not be configured to virtual local area network (VLAN) 4095 unless Virtual Guest Tagging (VGT) is required. When a port group is set to VLAN 4095, the vSwitch passes all network frames to the attached virtual machines (VMs) without modifying the VLAN tags. In vSphere, this is referred to as VGT. The VM must process the VLAN information itself via an 802.1Q driver in the operating system....
V-256424 Medium All port groups on standard switches must be configured to a value other than that of the native virtual local area network (VLAN). ESXi does not use the concept of native VLAN. Frames with a 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 belong to the native VLAN of the physical switch. For example, frames...
V-256423 Medium Use of the dvFilter network application programming interfaces (APIs) must be restricted. If the organization is not using products that use the dvfilter network API, the host should not be configured to send network information to a virtual machine (VM). If the API is enabled, an attacker might attempt to connect a virtual machine to it, potentially providing access to the network...
V-256422 Medium All port groups on standard switches must be configured to reject guest promiscuous mode requests. When promiscuous mode is enabled for a virtual switch, all virtual machines (VMs) connected to the Portgroup have the potential to read all packets across that network (only the virtual machines connected to that Portgroup). Promiscuous mode is disabled by default on the ESXi Server, and this is the recommended...
V-256420 Medium All port groups on standard switches must be configured to reject forged transmits. If the virtual machine (VM) operating system changes the Media Access Control (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...
V-256419 Medium The ESXi host must enable Bridge Protocol Data Units (BPDU) filter on the host to prevent being locked out of physical switch ports with Portfast and BPDU Guard enabled. BPDU Guard and Portfast are commonly enabled on the physical switch to which the ESXi host is directly connected to reduce the Spanning Tree Protocol (STP) convergence delay. If a BPDU packet is sent from a virtual machine (VM) on the ESXi host to the physical switch configured as stated...
V-256418 Medium The ESXi host must configure the firewall to block network traffic by default. 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 ensuring this is set to deny incoming and outgoing traffic.
V-256417 Medium The ESXi host must configure the firewall to restrict access to services running on the host. 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.
V-256415 Medium The ESXi host must enable bidirectional Challenge-Handshake Authentication Protocol (CHAP) authentication for Internet Small Computer Systems Interface (iSCSI) traffic. When enabled, vSphere performs bidirectional authentication of both the iSCSI target and host. When not authenticating both the iSCSI target and host, there is potential for a man-in-the-middle attack, in which an attacker might impersonate either side of the connection to steal data. Bidirectional authentication mitigates this risk.
V-256414 Medium Simple Network Management Protocol (SNMP) must be configured properly on the ESXi host. 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 use this information to plan an attack.
V-256413 Medium The ESXi host must protect the confidentiality and integrity of transmitted information by isolating IP-based storage traffic. Virtual machines (VMs) 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 VM users. IP-based storage frequently is not encrypted. It can be viewed by anyone with access to this network. To...
V-256412 Medium The ESXi host must protect the confidentiality and integrity of transmitted information by protecting ESXi management traffic. 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. The Management VMkernel port...
V-256411 Medium The ESXi host must protect the confidentiality and integrity of transmitted information by isolating vMotion traffic. While encrypted vMotion is available, vMotion traffic should still be sequestered from other traffic to further protect it from attack. This network must only be accessible to other ESXi hosts, preventing outside access to the network. The vMotion VMkernel port group must be in a dedicated VLAN that can be...
V-256409 Medium The ESXi host must configure NTP time synchronization. To ensure the accuracy of the system clock, it must be synchronized with an authoritative time source within DOD. Many system functions, including time-based logon 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...
V-256408 Medium The ESXi host must enable a persistent log location for all locally stored logs. 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....
V-256407 Medium The ESXi host must log out of the console UI after two minutes. When the Direct Console User Interface (DCUI) is enabled and logged in, it should be automatically logged out if left logged on to avoid access by unauthorized persons. The "DcuiTimeOut" setting defines a window of time after which the DCUI will be logged out.
V-256406 Medium The ESXi host must terminate shell services after 10 minutes. When the ESXi Shell or Secure Shell (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 be stopped automatically.
V-256405 Medium The ESXi host must set a timeout to automatically disable idle shell sessions after two minutes. If a user forgets to log out of their local or remote ESXi Shell session, the idle connection will remain open indefinitely and increase the likelihood of inappropriate host access via session hijacking. The "ESXiShellInteractiveTimeOut" allows the automatic termination of idle shell sessions. Satisfies: SRG-OS-000163-VMM-000700, SRG-OS-000279-VMM-001010
V-256404 Medium Active Directory ESX Admin group membership must not be used when adding ESXi hosts to Active Directory. When adding ESXi hosts to Active Directory, all user/group accounts assigned to the Active Directory group \"ESX Admins\" will have full administrative access to the host. If this group is not controlled or known to the system administrators, it may be used for inappropriate access to the host. Therefore, the...
V-256403 Medium ESXi hosts using Host Profiles and/or Auto Deploy must use the vSphere Authentication Proxy to protect passwords when adding themselves to Active Directory. If a host is configured to join an Active Directory domain using Host Profiles and/or Auto Deploy, the Active Directory credentials are saved in the 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...
V-256401 Medium The ESXi host must disable ESXi Shell unless needed for diagnostics or troubleshooting. The ESXi Shell is an interactive command line environment available locally from the Direct Console User Interface (DCUI) or remotely via SSH. Activities performed from the ESXi Shell bypass vCenter role-based access control (RBAC) and audit controls. The ESXi shell must only be turned on when needed to troubleshoot/resolve problems...
V-256400 Medium The ESXi host must be configured to disable nonessential capabilities by disabling Secure Shell (SSH). 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, which are not...
V-256399 Medium The ESXi host must disable the Managed Object Browser (MOB). The MOB provides a way to explore the object model used by the VMkernel to manage the host and enables configurations to be changed. This interface is meant to be used primarily for debugging the vSphere Software Development Kit (SDK), but because there are no access controls it could also...
V-256398 Medium The ESXi host must prohibit the reuse of passwords within five iterations. 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.
V-256397 Medium The ESXi host must be configured with a sufficiently complex password policy. 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...
V-256396 Medium The ESXi host must produce audit records containing information to establish what type of events occurred. 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. Satisfies: SRG-OS-000037-VMM-000150, SRG-OS-000063-VMM-000310
V-256393 Medium The ESXi host Secure Shell (SSH) daemon must not permit tunnels. 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 Access Control Lists (ACLs).
V-256392 Medium The ESXi host Secure Shell (SSH) daemon must be configured to not allow X11 forwarding. 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.
V-256390 Medium The ESXi host Secure Shell (SSH) daemon must not allow compression or must only allow compression after successful authentication. 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.
V-256389 Medium The ESXi host Secure Shell (SSH) daemon must perform strict mode checking of home directory configuration files. If other users have access to modify user-specific SSH configuration files, they may be able to log on the system as another user.
V-256388 Medium The ESXi host Secure Shell (SSH) daemon must not permit user environment settings. 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.
V-256386 Medium The ESXi host Secure Shell (SSH) daemon must not allow host-based authentication. 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 because hosts are cryptographically authenticated. However, it is not recommended that hosts unilaterally trust one another, even within an organization.
V-256385 Medium The ESXi host Secure Shell (SSH) daemon must ignore ".rhosts" files. 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.
V-256384 Medium The ESXi host Secure Shell (SSH) daemon must use FIPS 140-2 validated cryptographic modules to protect the confidentiality of remote access sessions. OpenSSH on the ESXi host ships with a FIPS 140-2 validated cryptographic module that is enabled by default. For backward compatibility reasons, this can be disabled so this setting can be audited and corrected if necessary.
V-256383 Medium The ESXi host SSH daemon must be configured with the DOD logon banner. 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 use of a banner that does not provide easy attribution.
V-256382 Medium The ESXi host must display the Standard Mandatory DOD Notice and Consent Banner before granting access to the system via Secure Shell (SSH). Failure to display the DOD logon banner prior to a logon attempt will negate legal proceedings resulting from unauthorized access to system resources.
V-256381 Medium The ESXi host must display the Standard Mandatory DOD Notice and Consent Banner before granting access to the system via the Direct Console User Interface (DCUI). Failure to display the DOD logon banner prior to a logon attempt will negate legal proceedings resulting from unauthorized access to system resources. Satisfies: SRG-OS-000023-VMM-000060, SRG-OS-000024-VMM-000070
V-256380 Medium The ESXi host must enforce an unlock timeout of 15 minutes after a user account is locked out. By enforcing a reasonable unlock timeout after multiple failed logon attempts, the risk of unauthorized access via user password guessing, otherwise known as brute forcing, is reduced. Users must wait for the timeout period to elapse before subsequent logon attempts are allowed.
V-256379 Medium The ESXi host must enforce the limit of three consecutive invalid logon attempts by a user. By limiting the number of failed logon attempts, the risk of unauthorized access via user password guessing, otherwise known as brute forcing, is reduced. Once the configured number of attempts is reached, the account is locked by the ESXi host.
V-256378 Medium Remote logging for ESXi hosts must be configured. 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...
V-256377 Medium The ESXi host must verify the exception users list for lockdown mode. While a host is in lockdown mode (strict or normal), only users on the "Exception Users" list are allowed access. These users do not lose their permissions when the host enters lockdown mode. The organization may want to add service accounts such as a backup agent to the Exception Users...
V-256376 Medium The ESXi host must verify the DCUI.Access list. Lockdown mode disables direct host access, requiring that administrators manage hosts from vCenter Server. However, if a host becomes isolated from vCenter, the administrator is locked out and can no longer manage the host. The "DCUI.Access" advanced setting allows specified users to exit lockdown mode in such a scenario. If...
V-256375 Medium Access to the ESXi host must be limited by enabling lockdown mode. Enabling lockdown mode disables direct access to an ESXi host, requiring the host to 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 on to a host directly. By forcing...
V-256416 Low The ESXi host must disable Inter-Virtual Machine (VM) Transparent Page Sharing. Published academic papers have demonstrated that by forcing a flush and reload of cache memory, it is possible to measure memory timings to try to determine an Advanced Encryption Standard (AES) encryption key in use on another virtual machine running on the same physical processor of the host server if...
V-256402 Low The ESXi host must use Active Directory for local user authentication. Join ESXi hosts to an Active Directory domain to eliminate the need to create and maintain multiple local user accounts. Using Active Directory 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:...
V-256395 Low The ESXi host Secure Shell (SSH) daemon must set a timeout interval on idle sessions. Automatically logging out idle users guards against compromises via hijacked administrative sessions.
V-256394 Low The ESXi host Secure Shell (SSH) daemon must set a timeout count on idle sessions. Setting a timeout ensures that a user login will be terminated as soon as the "ClientAliveCountMax" is reached.
V-256391 Low The ESXi host Secure Shell (SSH) daemon must be configured to not allow gateway ports. SSH Transmission Control Protocol (TCP) connection forwarding provides a mechanism to establish TCP connections proxied by the SSH server. This function can provide convenience similar to a virtual private network (VPN) with the similar risk of providing a path to circumvent firewalls and network Access Control Lists (ACLs). Gateway ports...
V-256387 Low The ESXi host Secure Shell (SSH) daemon must not allow authentication using an empty password. Configuring this setting for the SSH daemon provides additional assurance that remote logon via SSH will require a password, even in the event of misconfiguration elsewhere.