Arch Linux ASA-202309-14: Moderate PowerDNS-Recursor DoS Vulnerability

Arch Linux Security Advisory ASA-201504-27
=========================================
Severity: Low
Date    : 2015-04-24
CVE-ID  : CVE-2015-1868
Package : powerdns-recursor
Type    : denial of service
Remote  : Yes
Link    : https://wiki.archlinux.org/title/CVE

Summary
======
The package powerdns-recursor before version 3.7.2-1 is vulnerable to
denial of service.

Resolution
=========
Upgrade to 3.7.2-1.

# pacman -Syu "powerdns-recursor>=3.7.2-1"

The problem has been fixed upstream in version 3.7.2.

Workaround
=========
Exposure can be limited by configuring the allow-from setting so only
trusted users can query your nameserver.

Description
==========
A bug was discovered in our label decompression code, making it possible
for names to refer to themselves, thus causing a loop during
decompression. This loop is capped at a 1000 iterations by a failsafe,
making the issue harmless on most platforms.
However, on specific platforms, the recursion involved in these 1000
steps causes memory corruption leading to a quick crash, presumably
because the default stack is too small.

Impact
=====
A remote attacker is able to send queries for specifically configured
domains to trigger a flaw that may possibly lead to denial of service.

References
=========
/
https://access.redhat.com/security/cve/CVE-2015-1868
https://bugs.archlinux.org/task/44708