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V-22488

CAT II (Medium)

The SSH daemon must not allow compression or must only allow compression after successful authentication.

Rule ID

SV-46107r2_rule

STIG

SUSE Linux Enterprise Server v11 for System z Security Technical Implementation Guide

Version

V1R12

CCIs

CCI-000366

Discussion

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.

Check Content

Check the SSH daemon configuration for the compression setting.
# grep -i Compression /etc/ssh/sshd_config | egrep "no|delayed"
If the setting is missing or is commented out, this is a finding.
If the setting is present but is not set to "no" or "delayed", this is a finding.

Fix Text

Edit the SSH daemon configuration and add or edit the "Compression" setting value to "no" or "delayed".

Restart the SSH daemon.
# /sbin/service sshd restart