## PowerDNS Security Advisory 2010-01: PowerDNS Recursor up to and including 3.1.7.1 can be brought down and probably exploited

 * CVE: CVE-2009-4009
 * Date: 6th of January 2010
 * Affects: PowerDNS Recursor 3.1.7.1 and earlier
 * Not affected: No versions of the PowerDNS Authoritative ('pdns\_server') are affected.
 * Severity: Critical
 * Impact: Denial of Service, possible full system compromise
 * Exploit: Withheld
 * Solution: Upgrade to PowerDNS Recursor 3.1.7.2 or higher
 * Workaround: None. The risk of exploitation or denial of service can be decreased slightly by using the `allow-from` setting to only provide service to known users. The risk of a full system compromise can be reduced by running with a suitable reduced privilege user and group settings, and possibly chroot environment.

Using specially crafted packets, it is possible to force a buffer overflow in the PowerDNS Recursor, leading to a crash.

This vulnerability was discovered by a third party that (for now) prefers not to be named. PowerDNS is very grateful however for their help in improving PowerDNS security.
