Avahi: Denial of Service

1. Gentoo Linux Security Advisory

Advisory Reference	GLSA 200904-10 / avahi
Release Date	April 08, 2009
Latest Revision	April 08, 2009: 01
Impact	normal
Exploitable	remote

Package	Vulnerable versions	Unaffected versions	Architecture(s)
net-dns/avahi	< 0.6.24-r2	>= 0.6.24-r2	All supported architectures

Related bugreports: #260971

Synopsis

An error in Avahi might lead to a Denial of Service via network and CPU consumption.

2. Impact Information

Background

Avahi is a system that facilitates service discovery on a local network.

Description

Rob Leslie reported that the originates_from_local_legacy_unicast_socket() function in avahi-core/server.c does not account for the network byte order of a port number when processing incoming multicast packets, leading to a multicast packet storm.

Impact

A remote attacker could send specially crafted legacy unicast mDNS query packets to the Avahi daemon, resulting in a Denial of Service due to network bandwidth and CPU consumption.

3. Resolution Information

Workaround

There is no known workaround at this time.

Resolution

All Avahi users should upgrade to the latest version:

Code Listing 3.1: Resolution

# emerge --sync
# emerge --ask --oneshot --verbose ">=net-dns/avahi-0.6.24-r2"

4. References

CVE-2009-0758

Page updated April 08, 2009

Summary: This is a Gentoo Linux Security Advisory

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