Gentoo Logo

Dnsmasq: Poisoning and Denial of Service vulnerabilities


1.  Gentoo Linux Security Advisory

Version Information

Advisory Reference GLSA 200504-03 / Dnsmasq
Release Date April 04, 2005
Latest Revision April 04, 2005: 01
Impact low
Exploitable remote
Package Vulnerable versions Unaffected versions Architecture(s)
net-dns/dnsmasq < 2.22 >= 2.22 All supported architectures

Related bugreports: #86718


Dnsmasq is vulnerable to DNS cache poisoning attacks and a potential Denial of Service from the local network.

2.  Impact Information


Dnsmasq is a lightweight and easily-configurable DNS forwarder and DHCP server.


Dnsmasq does not properly detect that DNS replies received do not correspond to any DNS query that was sent. Rob Holland of the Gentoo Linux Security Audit team also discovered two off-by-one buffer overflows that could crash DHCP lease files parsing.


A remote attacker could send malicious answers to insert arbitrary DNS data into the Dnsmasq cache. These attacks would in turn help an attacker to perform man-in-the-middle and site impersonation attacks. The buffer overflows might allow an attacker on the local network to crash Dnsmasq upon restart.

3.  Resolution Information


There is no known workaround at this time.


All Dnsmasq users should upgrade to the latest version:

Code Listing 3.1: Resolution

# emerge --sync
# emerge --ask --oneshot --verbose ">=net-dns/dnsmasq-2.22"

4.  References


Page updated April 04, 2005

Summary: This is a Gentoo Linux Security Advisory

Security Team
Contact Address

Donate to support our development efforts.

Copyright 2001-2015 Gentoo Foundation, Inc. Questions, Comments? Contact us.