[arch-security] [ASA-201504-27] powerdns-recursor: denial of service

[Levente Polyak]

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/index.php/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://doc.powerdns.com/md/security/powerdns-advisory-2015-01/
https://access.redhat.com/security/cve/CVE-2015-1868
https://bugs.archlinux.org/task/44708

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