The SSH client must not permit GSSAPI authentication unless needed.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-22474	GEN005525	SV-35068r1_rule	ECSC-1	Low

Description
GSSAPI authentication is used to provide additional authentication mechanisms to applications. Allowing GSSAPI authentication through SSH exposes the system’s GSSAPI to remote hosts, increasing the attack surface of the system. GSSAPI authentication must be disabled unless needed.

STIG	Date
HP-UX 11.31 Security Technical Implementation Guide	2018-03-01

Details

Check Text ( C-34935r1_chk )
Check the SSH client configuration. Note that keywords are case-insensitive and arguments (args) are case-sensitive. keyword=GSSAPIAuthentication arg(s)=no Default values include: "no" Note: When the default "arg" value exactly matches the required "arg" value (see above), the entry is not required to exist (commented or uncommented) in the ssh (client) or sshd (server) configuration file. While not required, it is recommended that the configuration file(s) be populated with all keywords and assigned arg values as a means to explicitly document the ssh(d) binary's expected behavior. Examine the file. # cat /opt/ssh/etc/ssh_config \| tr '\011' ' ' \| tr -s ' ' \| sed -e 's/^[ \t]*//' \| grep -v '^#' \| grep -i "GSSAPIAuthentication" If the return value is yes, this is a finding.

Check Text ( C-34935r1_chk )

Check the SSH client configuration. Note that keywords are case-insensitive and arguments (args) are case-sensitive.

keyword=GSSAPIAuthentication
arg(s)=no

Default values include: "no"

Note: When the default "arg" value exactly matches the required "arg" value (see above), the entry is not required to exist (commented or uncommented) in the ssh (client) or sshd (server) configuration file. While not required, it is recommended that the configuration file(s) be populated with all keywords and assigned arg values as a means to explicitly document the ssh(d) binary's expected behavior.

Examine the file.
# cat /opt/ssh/etc/ssh_config | tr '\011' ' ' | tr -s ' ' | sed -e 's/^[ \t]*//' | grep -v '^#' | grep -i "GSSAPIAuthentication"

If the return value is yes, this is a finding.

Fix Text (F-30241r1_fix)
Edit the configuration file and set/add (if necessary) the GSSAPIAuthentication directive set to no.