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cis-ubuntu1804-v220-4-2-13

DevOps & Security
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Ensure sshd LogLevel is configured

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Source SKILL.md: https://github.com/CyberStrikeus/CyberStrike/blob/HEAD/.cyberstrike/skill/CIS_benchmarks/Operating_Systems/Ubuntu/CIS_Ubuntu_Linux_18.04_LTS_Benchmark_v2.2.0/cis-ubuntu1804-v220-4-2-13/SKILL.md

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CIS Ubuntu Linux 18.04 LTS Benchmark v2.2.0 - Control 4.2.13

Profile Applicability

  • Level 1 - Server
  • Level 1 - Workstation

Description

SSH provides several logging levels with varying amounts of verbosity. DEBUG is specifically not recommended other than strictly for debugging SSH communications since it provides so much data that it is difficult to identify important security information.

Rationale

SSH LogLevel should be set to VERBOSE or INFO level. This ensures login and logout activity, as well as key fingerprints, are logged. The INFO level outputs only minimal information, while VERBOSE provides additional SSH key information.

Audit Procedure

Command Line

Run the following command and verify the output:

sshd -T | grep -i loglevel

Expected Result

loglevel VERBOSE

OR

loglevel INFO

Remediation

Command Line

Edit the /etc/ssh/sshd_config file to set the parameter as follows:

LogLevel VERBOSE

Default Value

LogLevel INFO

References

  1. NIST SP 800-53 Rev. 5: AU-3, AU-12

CIS Controls

v8 - 8.5 Collect Detailed Audit Logs - Configure detailed audit logging for enterprise assets containing sensitive data.

v7 - 6.2 Activate Audit Logging - Ensure that local logging has been enabled on all systems and networking devices.

Profile Applicability

  • Level 1 - Server
  • Level 1 - Workstation

Assessment Status

Automated