The ESXi host Secure Shell (SSH) daemon must not allow compression or must only allow compression after successful authentication.
Severity | Group ID | Group Title | Version | Rule ID | Date | STIG Version |
|---|---|---|---|---|---|---|
| medium | V-256390 | SRG-OS-000480-VMM-002000 | ESXI-70-000021 | SV-256390r959010_rule | 2025-02-11 | 1 |
| Description |
|---|
| 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. |
| ℹ️ Check |
|---|
| From an ESXi shell, run the following command: # /usr/lib/vmware/openssh/bin/sshd -T|grep compression Expected result: compression no If the output does not match the expected result, this is a finding. |
| ✔️ Fix |
|---|
| From an ESXi shell, add or correct the following line in "/etc/ssh/sshd_config": Compression no |