dnsmasq: Denial of Service and DNS spoofing

Security Team Contact Address

Updated September 04, 2008

1. Gentoo Linux Security Advisory

Advisory Reference	GLSA 200809-02 / dnsmasq
Release Date	September 04, 2008
Latest Revision	September 04, 2008: 01
Impact	normal
Exploitable	remote

Package	Vulnerable versions	Unaffected versions	Architecture(s)
net-dns/dnsmasq	< 2.45	>= 2.45	All supported architectures

Related bugreports: #231282, #232523

Synopsis

Two vulnerabilities in dnsmasq might allow for a Denial of Service or spoofing of DNS replies.

2. Impact Information

Background

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

Description

Dan Kaminsky of IOActive reported that dnsmasq does not randomize UDP source ports when forwarding DNS queries to a recursing DNS server (CVE-2008-1447).
Carlos Carvalho reported that dnsmasq in the 2.43 version does not properly handle clients sending inform or renewal queries for unknown DHCP leases, leading to a crash (CVE-2008-3350).

Impact

A remote attacker could send spoofed DNS response traffic to dnsmasq, possibly involving generating queries via multiple vectors, and spoof DNS replies, which could e.g. lead to the redirection of web or mail traffic to malicious sites. Furthermore, an attacker could generate invalid DHCP traffic and cause a Denial of Service.

3. Resolution Information

Workaround

There is no known workaround at this time.

Resolution

All dnsmasq users should upgrade to the latest version:

Code Listing 3.1: Resolution

# emerge --sync
# emerge --ask --oneshot --verbose ">=net-dns/dnsmasq-2.45"

4. References