The SSH daemon must not permit user environment settings.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-22479	GEN005530	SV-26773r1_rule	ECSC-1	Low

Description
SSH may be used to provide limited functions other than an interactive shell session, such as file transfer. If local, user-defined environment settings (such as, those configured in ~/.ssh/authorized_keys and ~/.ssh/environment) are configured by the user and permitted by the SSH daemon, they could be used to alter the behavior of the limited functions, potentially granting unauthorized access to the system.

Description

SSH may be used to provide limited functions other than an interactive shell session, such as file transfer. If local, user-defined environment settings (such as, those configured in ~/.ssh/authorized_keys and ~/.ssh/environment) are configured by the user and permitted by the SSH daemon, they could be used to alter the behavior of the limited functions, potentially granting unauthorized access to the system.

STIG	Date
UNIX SRG	2013-03-26

Details

Check Text ( C-27781r1_chk )
Check the PermitUserEnvironment setting in the SSH daemon configuration. Procedure: # grep -i PermitUserEnvironment sshd_config If the setting is not present or set to a value other than no, this is a finding.

Fix Text (F-24023r1_fix)
Edit the SSH daemon configuration and edit (or add) the PermitUserEnvironment setting with a value of no.