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CIS Ubuntu 14.04 LTS - 5.2.15 Ensure SSH warning banner is configured

DevOps & Security
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Verify SSH Banner is configured to display a warning message before authentication

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How to use this skill

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I want to install this Agent Skill for this project in Codex.

Source SKILL.md: https://github.com/CyberStrikeus/CyberStrike/blob/HEAD/.cyberstrike/skill/CIS_benchmarks/Operating_Systems/Ubuntu/CIS_Ubuntu_Linux_14.04_LTS_Benchmark_v2.1.0/cis-ubuntu1404-v210-5-2-15/SKILL.md

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First, summarize what it does, its dependencies, license status if identifiable, and any risks. Show the exact files you propose to add under .agents/skills/cis-ubuntu-14-04-lts-5-2-15-ensure-ssh-warning-banner-is-configured/. Do not write files or run scripts until I approve.

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5.2.15 Ensure SSH warning banner is configured (Scored)

Profile Applicability

  • Level 1 - Server
  • Level 1 - Workstation

Description

The Banner parameter specifies a file whose contents must be sent to the remote user before authentication is permitted. By default, no banner is displayed.

Rationale

Banners are used to warn connecting users of the particular site's policy regarding connection. Presenting a warning message prior to the normal user login may assist the prosecution of trespassers on the computer system.

Audit Procedure

Run the following command and verify that output matches:

grep "^Banner" /etc/ssh/sshd_config

Expected Result

Banner /etc/issue.net

Remediation

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

Banner /etc/issue.net

Default Value

Banner none

References

  • CIS Controls: 16 - Account Monitoring and Control

Profile

  • Level 1 - Server
  • Level 1 - Workstation