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Cis Bind V100 10 4

DevOps & Security
cis-bind-v100-10-4

Cis Bind V100 10 4 is an Agent Skill for devops & security published in the CyberStrikeus/CyberStrike repository on GitHub: a SKILL.md instruction file an AI agent can load to do this task.

Ensure Only the Necessary SELinux Booleans are Enabled (Automated)

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  2. Copy and paste the prompt below.
  3. Review files and risks before approving any action.
Prompt to paste
Inspect the Agent Skill at https://github.com/CyberStrikeus/CyberStrike/blob/HEAD/.cyberstrike/skill/CIS_benchmarks/Server_Software/Bind/CIS_ISC_BIND_DNS_Server_9.11_Benchmark_v1.0.0/cis-bind-v100-10-4/SKILL.md and all supporting files. Report provenance, permissions, scripts, dependencies, and security risks. Propose an exact installation into .agents/skills/cis-bind-v100-10-4, but wait for my approval before writing files or running scripts.

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

CIS 10.4 — Ensure Only the Necessary SELinux Booleans are Enabled

Profile Applicability

  • Caching Only Name Server Level 2
  • Authoritative Name Server Level 2

Description

SELinux booleans allow or disallow specific behaviors. There are two boolean variables specific to the ISC BIND DNS server:

  • named_tcp_bind_http_port - Allow named to tcp bind http port
  • named_write_master_zones - Allow named to write master zones

The named_tcp_bind_http_port would allow enabling the BIND statistics http channel which is not recommended. The named_write_master_zones allows BIND to update the master files, which is necessary when dynamic updates are performed, or the server is automatically maintaining DNSSEC digital signatures.

Rationale

Enabling only the necessary named related booleans provides a defense in depth approach, that will deny actions that are not in use or expected.

Impact

Not specified.

Audit Procedure

Perform the following steps to determine if the recommended state is implemented:

Use getsebool to verify the named_tcp_bind_http_port boolean has a value of off.

# getsebool named_tcp_bind_http_port
named_tcp_bind_http_port --> off

The named_write_master_zones boolean is not audited as many BIND servers will require the boolean to be enabled.

Remediation

Perform the following to implement the recommended state:

Disable the SELinux boolean using the setsebool command as shown below with the -P option to make the change persistent.

# setsebool -P named_tcp_bind_http_port off

Default Value

The default value for named_tcp_bind_http_port is off.

References

None listed in benchmark.

CIS Controls

Controls VersionControlIG 1IG 2IG 3
v79.2 Ensure Only Approved Ports, Protocols and Services Are RunningNYY

MITRE ATT&CK Mappings

TacticTechnique
Defense EvasionT1562 Impair Defenses

Profile

  • Level 2 - Authoritative Name Server
  • Level 2 - Caching Only Name Server