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 src.

Base

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

Temporal

• Exploit code maturity: 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

Score 4.0

Default score using CVSS 4.0. It may change depending on the context of the src.

Base 4.0

• Attack vector: A
• Attack complexity: H
• Attack Requirements: N
• Privileges required: N
• User interaction: N
• Confidentiality (VC): N
• Integrity (VI): N
• Availability (VA): L
• Confidentiality (SC): N
• Integrity (SI): N
• Availability (SA): N

Threat 4.0

• Exploit maturity: X

Result 4.0

• Vector string: CVSS:4.0/AV:A/AC:H/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X
• Score:
• CVSS-BT: 2.3
• Severity:
• CVSS-BT: Low

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

• 266.Disable insecure functionalities

Fixes

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