PowerDNS Security Advisory 2015-02: Packet parsing bug can cause thread or process abortion

• CVE: CVE-2015-5230
• Date: 2nd of September 2015
• Credit: Pyry Hakulinen and Ashish Shukla at Automattic
• Affects: PowerDNS Authoritative Server 3.4.0 through 3.4.5
• Not affected: PowerDNS Authoritative Server 3.4.6
• Severity: High
• Impact: Degraded service or Denial of service
• Exploit: This problem can be triggered by sending specially crafted query packets
• Risk of system compromise: No
• Solution: Upgrade to a non-affected version
• Workaround: Run the Authoritative Server inside a supervisor when distributor-threads is set to 1 to prevent Denial of Service. No workaround for the degraded service exists

A bug was found in our DNS packet parsing/generation code, which, when exploited, can cause individual threads (disabling service) or whole processes (allowing a supervisor to restart them) to crash with just one or a few query packets.

PowerDNS Authoritative Server 3.4.0-3.4.5 are affected. No other versions are affected. The PowerDNS Recursor is not affected.

PowerDNS Authoritative Server 3.4.6 contains a fix to this issue. A minimal patch is available here.

This issue is entirely unrelated to Security Advisory 2015-01/CVE-2015-1868.

We’d like to thank Pyry Hakulinen and Ashish Shukla at Automattic for finding and subsequently reporting this bug.