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CIS Ubuntu 14.04 LTS - 5.2.2 Ensure SSH Protocol is set to 2

DevOps & Security
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Verify SSH is configured to use Protocol version 2 only

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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-v210-5-2-2/SKILL.md

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5.2.2 Ensure SSH Protocol is set to 2 (Scored)

Profile Applicability

  • Level 1 - Server
  • Level 1 - Workstation

Description

SSH supports two different and incompatible protocols: SSH1 and SSH2. SSH1 was the original protocol and was subject to security issues. SSH2 is more advanced and secure.

Rationale

SSH v1 suffers from insecurities that do not affect SSH v2.

Audit Procedure

Run the following command and verify that output matches:

grep "^Protocol" /etc/ssh/sshd_config

Expected Result

Protocol 2

Remediation

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

Protocol 2

Default Value

Protocol 2

References

  • CIS Controls: 3.4 - Use Only Secure Channels For Remote System Administration

Profile

  • Level 1 - Server
  • Level 1 - Workstation