GLSA 200901-03: pdnsd: Denial of Service and cache poisoning

http://security.gentoo.org/

Severity:	normal
Title:	pdnsd: Denial of Service and cache poisoning
Date:	01/11/2009
Bugs:	#231285
ID:	200901-03

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	Architecture(s)
net-dns/pdnsd	< 1.2.7	>= 1.2.7	All supported architectures

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 ">=net-dns/pdnsd-1.2.7"

References

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 https://bugs.gentoo.org.