dnsmasq: Denial of Service and DNS spoofing

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.

Workaround

There is no known workaround at this time.

Resolution

All dnsmasq users should upgrade to the latest version:

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