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

V-22475

CAT III (Low)

The SSH daemon must not permit Kerberos authentication unless needed.

Rule ID

SV-46087r2_rule

STIG

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

Version

V1R12

CCIs

CCI-000366

Discussion

Kerberos authentication for SSH is often implemented using GSSAPI. If Kerberos is enabled through SSH, the SSH daemon provides a means of access to the system's Kerberos implementation. Vulnerabilities in the system's Kerberos implementation may then be subject to exploitation. To reduce the attack surface of the system, the Kerberos authentication mechanism within SSH must be disabled for systems not using this capability.

Check Content

Ask the SA if Kerberos authentication is used by the system. If it is, this is not applicable.

Check the SSH daemon configuration for the KerberosAuthentication setting.
# grep -i KerberosAuthentication /etc/ssh/sshd_config | grep -v '^#' 
If no lines are returned, or the setting is set to "yes", this is a finding.

Fix Text

Edit the SSH daemon configuration and set (add if necessary) the "KerberosAuthentication" directive set to "no".

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