Details

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. Promiscuous Mode can be set at the vSwitch and/or the Portgroup level. Switch-level settings can be overridden at the Portgroup level.

Solution

From the vSphere Client go to Configure >> Networking >> Virtual Switches.

For each virtual switch and port group, click Edit settings (dots) 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

Supportive Information

The following resource is also helpful.

• https://dl.dod.cyber.mil/wp-content/uploads/stigs/zip/U_VMW_vSphere_6-7_STIG.zip

This security hardening control applies to the following category of controls within NIST 800-53: Configuration Management.This control applies to the following type of system VMware.

References

• 800-53|CM-6b.
• CAT|II
• CCI|CCI-000366
• Rule-ID|SV-239315r674874_rule
• STIG-ID|ESXI-67-000061
• STIG-Legacy|SV-104155
• STIG-Legacy|V-94069
• Vuln-ID|V-239315

Source

• Tenable.com/audits