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CIS Ubuntu 14.04 LTS - 2.1.7 Ensure talk server is not enabled

DevOps & Security
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Verify that talk inetd services are disabled to reduce attack surface

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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-v210-2-1-7/SKILL.md

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2.1.7 Ensure talk server is not enabled (Scored)

Profile Applicability

  • Level 1 - Server
  • Level 1 - Workstation

Description

The talk software makes it possible for users to send and receive messages across systems through a terminal session. The talk client (allows initiate of talk sessions) is installed by default.

Rationale

The software presents a security risk as it uses unencrypted protocols for communication.

Audit Procedure

Verify the talk service is not enabled. Run the following commands and verify results are as indicated:

grep -R "^talk" /etc/inetd.*
grep -R "^ntalk" /etc/inetd.*

No results should be returned.

Check /etc/xinetd.conf and /etc/xinetd.d/* and verify all talk services have disable = yes set.

Expected Result

No output should be returned from the grep commands. All talk services in xinetd should have disable = yes.

Remediation

Comment out or remove any lines starting with talk or ntalk from /etc/inetd.conf and /etc/inetd.d/*.

Set disable = yes on all talk services in /etc/xinetd.conf and /etc/xinetd.d/*.

Default Value

talk services are not enabled by default.

References

  • CIS Controls: 9.1 Limit Open Ports, Protocols, and Services

Profile

  • Level 1 - Server
  • Level 1 - Workstation