PowerDNS Security Advisory 2016-05: Crafted zone record can cause a denial of service

  • CVE: CVE-2016-2120
  • Date: December 15th 2016
  • Credit: Mathieu Lafon
  • Affects: PowerDNS Authoritative Server up to and including 3.4.10, 4.0.1
  • Not affected: PowerDNS Authoritative Server 3.4.11, 4.0.2
  • Severity: Medium
  • Impact: Denial of service
  • Exploit: This issue can be triggered by inserting a specially crafted record in a zone
  • Risk of system compromise: No
  • Solution: Upgrade to a non-affected version

An issue has been found in PowerDNS Authoritative Server allowing an authorized user to crash the server by inserting a specially crafted record in a zone under their control then sending a DNS query for that record. The issue is due to an integer overflow when checking if the content of the record matches the expected size, allowing an attacker to cause a read past the buffer boundary. This issue has been assigned CVE-2016-2120.

PowerDNS Authoritative Server up to and including 3.4.10 and 4.0.1 are affected. The PowerDNS Recursor is not affected.

For those unable to upgrade to a new version, a minimal patch is available

We would like to thank Mathieu Lafon for finding and subsequently reporting this issue.