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CIS Ubuntu 14.04 LTS - 2.2.3 Ensure Avahi Server is not enabled

DevOps & Security
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Verify that Avahi mDNS/DNS-SD daemon is disabled to reduce attack surface

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How to use this skill

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  3. Review the proposed files and risks before you approve installation.
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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-v210-2-2-3/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-2-2-3-ensure-avahi-server-is-not-enabled/. Do not write files or run scripts until I approve.

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Copying this prompt does not install or run the skill. Review third-party files before use. Codex skill guide

2.2.3 Ensure Avahi Server is not enabled (Scored)

Profile Applicability

  • Level 1 - Server
  • Level 1 - Workstation

Description

Avahi is a free zeroconf implementation, including a system for multicast DNS/DNS-SD service discovery. Avahi allows programs to publish and discover services and hosts running on a local network with no specific configuration. For example, a user can plug a computer into a network and Avahi automatically finds printers to print to, files to look at and people to talk to, as well as network services running on the machine.

Rationale

Automatic discovery of network services is not normally required for system functionality. It is recommended to disable the service to reduce the potential attack surface.

Audit Procedure

Run the following commands to verify no start conditions listed for avahi-daemon:

initctl show-config avahi-daemon

Verify the output shows avahi-daemon with no start conditions.

Expected Result

The avahi-daemon service should have no start conditions listed.

Remediation

Remove or comment out start lines in /etc/init/avahi-daemon.conf:

#start on runlevel [2345]

Default Value

Avahi may be enabled by default on desktop installations.

References

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

Profile

  • Level 1 - Server
  • Level 1 - Workstation