GLSA 200901-03 pdnsd: Denial of Service and cache poisoning
Posted on: 01/11/2009 03:05 AM

A new security update has been released for Gentoo Linux - pdnsd: Denial of Service and cache poisoning. Here the announcement:

Gentoo Linux Security Advisory GLSA 200901-03
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http://security.gentoo.org/
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Severity: Normal
Title: pdnsd: Denial of Service and cache poisoning
Date: January 11, 2009
Bugs: #231285
ID: 200901-03

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Synopsis
========

Two errors in pdnsd allow for Denial of Service and cache poisoning.

Background
==========

pdnsd is a proxy DNS server with permanent caching that is designed to
cope with unreachable DNS servers.

Affected packages
=================

-------------------------------------------------------------------
Package / Vulnerable / Unaffected
-------------------------------------------------------------------
1 net-dns/pdnsd lt; 1.2.7 gt;= 1.2.7

Description
===========

Two issues have been reported in pdnsd:

* The p_exec_query() function in src/dns_query.c does not properly
handle many entries in the answer section of a DNS reply, related to
a "dangling pointer bug" (CVE-2008-4194).

* The default value for query_port_start was set to 0, disabling UDP
source port randomization for outgoing queries (CVE-2008-1447).

Impact
======

An attacker could exploit the second weakness to poison the cache of
pdnsd and thus spoof DNS traffic, which could e.g. lead to the
redirection of web or mail traffic to malicious sites. The first issue
can be exploited by enticing pdnsd to send a query to a malicious DNS
server, or using the port randomization weakness, and might lead to a
Denial of Service.

Workaround
==========

Port randomization can be enabled by setting the "query_port_start"
option to 1024 which would resolve the CVE-2008-1447 issue.

Resolution
==========

All pdnsd users should upgrade to the latest version:

# emerge --sync
# emerge --ask --oneshot --verbose "gt;=net-dns/pdnsd-1.2.7"

References
==========

[ 1 ] CVE-2008-1447
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2008-1447
[ 2 ] CVE-2008-4194
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2008-4194

Availability
============

This GLSA and any updates to it are available for viewing at
the Gentoo Security Website:

http://security.gentoo.org/glsa/glsa-200901-03.xml

Concerns?
=========

Security is a primary focus of Gentoo Linux and ensuring the
confidentiality and security of our users machines is of utmost
importance to us. Any security concerns should be addressed to
security@gentoo.org or alternatively, you may file a bug at
http://bugs.gentoo.org.

License
=======

Copyright 2009 Gentoo Foundation, Inc; referenced text
belongs to its owner(s).

The contents of this document are licensed under the
Creative Commons - Attribution / Share Alike license.

http://creativecommons.org/licenses/by-sa/2.5



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