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Avahi: Denial of Service


1.  Gentoo Linux Security Advisory

Version Information

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


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

2.  Impact Information


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


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.


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


There is no known workaround at this time.


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


Page updated April 08, 2009

Summary: This is a Gentoo Linux Security Advisory

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