4.7.3.10 Ensure sshd LogLevel is configured

Information

SSH provides several logging levels with varying amounts of verbosity. The DEBUG options are specifically not recommended other than strictly for debugging SSH communications. These levels provide so much data that it is difficult to identify important security information, and may violate the privacy of users.

The INFO level is the basic level that only records login activity of SSH users. In many situations, such as Incident Response, it is important to determine when a particular user was active on a system. The logout record can eliminate those users who disconnected, which helps narrow the field.

The VERBOSE level specifies that login and logout activity as well as the key fingerprint for any SSH key used for login will be logged. This information is important for SSH key management, especially in legacy environments.

Solution

Edit the /etc/ssh/sshd_config file to set the parameter above any Match set entries as follows:

LogLevel VERBOSE
- OR -
LogLevel INFO

Re-cycle the sshd daemon to pick up the configuration changes:

stopsrc -s sshd
startsrc -s sshd

Note: First occurrence of a option takes precedence, Match set statements withstanding.

See Also

https://workbench.cisecurity.org/benchmarks/10385

Item Details

Category: AUDIT AND ACCOUNTABILITY

References: 800-53|AU-2, 800-53|AU-7, 800-53|AU-12, CSCv7|6.2, CSCv7|6.3

Plugin: Unix

Control ID: a7ccb817ca612e3926c48716f9eaaee60f72d3ee8ef586803cf6218bc1120f7c