The SSH daemon must not permit Kerberos authentication unless needed.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-22475	GEN005526	SV-40716r1_rule	ECSC-1	Low

Description
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.

Description

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.

STIG	Date
AIX 5.3 SECURITY TECHNICAL IMPLEMENTATION GUIDE	2014-10-03

Details

Check Text ( C-39447r1_chk )
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 Kerberos authentication setting. # grep -i KerberosAuthentication /etc/ssh/sshd_config \| grep -v '^#' If the setting is present and set to "yes", this is a finding. If the setting is missing or set to "no", this is not a finding.

Fix Text (F-34575r1_fix)
Edit the /etc/ssh/sshd_config file and remove the KerberosAuthentication setting or change the value of the setting to "no".