CVE-2018-14644 : Exploit Details and Defense Strategies

PowerDNS Recursor versions 4.0.0 to 4.1.4 are affected by a vulnerability that can lead to incorrect DNSSEC validation caching, resulting in ServFail responses.

Understanding CVE-2018-14644

A vulnerability in PowerDNS Recursor versions 4.0.0 to 4.1.4 allows remote attackers to trigger incorrect DNSSEC validation caching.

What is CVE-2018-14644?

The issue occurs when a DNS query for a meta-type like OPT is sent, causing a zone to be inaccurately cached as failing DNSSEC validation.

The Impact of CVE-2018-14644

CVSS Base Score: 5.3 (Medium)
Attack Vector: Network
Attack Complexity: Low
Availability Impact: Low
No impact on Confidentiality or Integrity

Technical Details of CVE-2018-14644

PowerDNS Recursor vulnerability details

Vulnerability Description

Remote attackers can trigger incorrect DNSSEC validation caching
Parent zone signing and FORMERR responses lead to ServFail responses

Affected Systems and Versions

Product: PowerDNS Recursor
Versions: 4.0.9, 4.1.5

Exploitation Mechanism

Attackers send DNS queries for specific meta-types like OPT
All authoritative servers for the parent zone respond with FORMERR

Mitigation and Prevention

Protecting against CVE-2018-14644

Immediate Steps to Take

Update PowerDNS Recursor to versions beyond 4.1.4
Monitor DNS queries for unusual patterns

Long-Term Security Practices

Regularly review and update DNS server configurations
Implement DNSSEC best practices

Patching and Updates

Apply patches provided by PowerDNS to address the vulnerability