The ESXi host must configure the firewall to block network traffic by default.
Severity | Group ID | Group Title | Version | Rule ID | Date | STIG Version |
|---|---|---|---|---|---|---|
| medium | V-256418 | SRG-OS-000480-VMM-002000 | ESXI-70-000057 | SV-256418r959010_rule | 2025-02-11 | 1 |
Description
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.
ℹ️ Check
From an ESXi shell, run the following command:
# esxcli network firewall get
If the "Default Action" does not equal "DROP", this is a finding.
or
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 an ESXi shell, run the following command:
# esxcli network firewall set --default-action=false
or
From a PowerCLI command prompt while connected to the ESXi host, run the following command:
Get-VMHostFirewallDefaultPolicy | Set-VMHostFirewallDefaultPolicy -AllowIncoming $false -AllowOutgoing $false