The SSH daemon must not permit Kerberos authentication.

From VMware vSphere ESXi 6.0 Security Technical Implementation Guide

Part of SRG-OS-000480-VMM-002000

Associated with: CCI-000366

SV-77697r1_rule The SSH daemon must not permit Kerberos authentication.

Vulnerability 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.

Check content

To verify the KerberosAuthentication setting, run the following command: # grep -i "^KerberosAuthentication" /etc/ssh/sshd_config If there is no output or the output is not exactly "KerberosAuthentication no", this is a finding.

Fix text

To set the KerberosAuthentication setting, add or correct the following line in "/etc/ssh/sshd_config": KerberosAuthentication no

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