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The Photon operating system must configure sshd to disallow compression of the encrypted session stream.


Finding ID Version Rule ID IA Controls Severity
V-239161 PHTN-67-000090 SV-239161r675291_rule Medium
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.
VMware vSphere 6.7 Photon OS Security Technical Implementation Guide 2022-06-17


Check Text ( C-42372r675289_chk )
At the command line, execute the following command:

# sshd -T|&grep -i Compression

Expected result:

Compression no

If the output does not match the expected result, this is a finding.
Fix Text (F-42331r675290_fix)
Open /etc/ssh/sshd_config with a text editor.

Ensure that the "Compression" line is uncommented and set to the following:

Compression no

At the command line, execute the following command:

# service sshd reload