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Insecure service configuration - DNS

Description​

The DNS server has recursive DNS functionality, which can allow an attacker to perform an amplification attack through it and cause another server to crash.

Impact​

Perform amplification attacks to cause DDos.

Recommendation​

Disable recursive DNS functionality on the server.

Threat​

Anonymous attacker from internal network.

Expected Remediation Time​

⌚ 30 minutes.

Score​

Default score using CVSS 3.1. It may change depending on the context of the vulnerability.

Base​

  • Attack vector: A
  • Attack complexity: H
  • Privileges required: N
  • User interaction: N
  • Scope: U
  • Confidentiality: N
  • Integrity: N
  • Availability: L

Temporal​

  • Exploit code madurity: X
  • Remediation level: X
  • Report confidence: X

Result​

  • Vector string: CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L/E:X/RL:X/RC:X
  • Score:
    • Base: 3.1
    • Temporal: 3.1
  • Severity:
    • Base: Low
    • Temporal: Low

Code Examples​

Compliant code​

The DNS server has no recursion services allowed

vars:
  app_fqdn: myapp
  timezone: "tz2"
  dns_servers: ["myserver"]
  dns_recursion_settings: "none"

Non compliant code​

The DNS servers allow recursive settings

vars:
  app_fqdn: myapp
  timezone: "tz2"
  dns_servers: ["myserver"]
  dns_recursion_settings: "Any"

Requirements​

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