The ESXi host Secure Shell (SSH) daemon must not allow compression or must only allow compression after successful authentication.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-256390	ESXI-70-000021	SV-256390r885951_rule		Medium

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.

STIG	Date
VMware vSphere 7.0 ESXi Security Technical Implementation Guide	2023-06-21

Details

Check Text ( C-60065r885949_chk )
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 Text (F-60008r885950_fix)
From an ESXi shell, add or correct the following line in "/etc/ssh/sshd_config": Compression no