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

V-22459

CAT II (Medium)

The SSH daemon must be configured to not use Cipher-Block Chaining (CBC) ciphers.

Rule ID

SV-46010r2_rule

STIG

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

Version

V1R12

CCIs

CCI-000366

Discussion

The Cipher-Block Chaining (CBC) mode of encryption as implemented in the SSHv2 protocol is vulnerable to chosen plain text attacks and must not be used.

Check Content

Check the SSH daemon configuration for allowed ciphers.
# grep -i ciphers /etc/ssh/sshd_config | grep -v '^#' 
If no lines are returned, or the returned ciphers list contains any cipher ending with "cbc", this is a finding.

Fix Text

Edit the SSH daemon configuration and remove any ciphers ending with "cbc". If necessary, add a "Ciphers" line.

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