| name | cis-ubuntu1804-v220-2-3-4 |
| description | Ensure telnet client is not installed |
| category | cis-networking |
| version | 2.2.0 |
| author | cyberstrike-official |
| tags | ["cis","ubuntu","linux","ubuntu-18.04","services","telnet-client"] |
| cis_id | 2.3.4 |
| cis_benchmark | CIS Ubuntu Linux 18.04 LTS Benchmark v2.2.0 |
| tech_stack | ["ubuntu","linux"] |
| cwe_ids | [] |
| chains_with | [] |
| prerequisites | [] |
| severity_boost | {} |
2.3.4 Ensure telnet client is not installed (Automated)
Profile
- Level 1 - Server
- Level 1 - Workstation
Description
The telnet package contains the telnet client, which allows users to start connections to other systems via the telnet protocol.
Rationale
The telnet protocol is insecure and unencrypted. The use of an unencrypted transmission medium could allow an unauthorized user to steal credentials. The ssh package provides an encrypted session and stronger security and is included in most Linux distributions.
Impact
Many insecure service clients are used as troubleshooting tools and in testing environments. Uninstalling them can inhibit capability to test and troubleshoot. If they are required it is advisable to remove the clients after use to prevent accidental or intentional misuse.
Audit Procedure
Command Line
Verify telnet is not installed. Use the following command to provide the needed information:
Nothing should be returned.
Expected Result
No output (empty result).
Remediation
Command Line
Uninstall telnet:
References
- NIST SP 800-53 Rev. 5: CM-7, CM-11
CIS Controls
- v8: 4.8 - Uninstall or Disable Unnecessary Services on Enterprise Assets and Software
- v7: 9.2 - Ensure Only Approved Ports, Protocols and Services Are Running