registry.pl in Fonality Trixbox 2.0 PBX products, when running in certain environments, reads and executes a set of commands from a remote web site without sufficiently validating the origin of the commands, which allows remote attackers to disable trixbox and execute arbitrary commands via a DNS spoofing attack.
http://www.trixbox.org/forums/trixbox-forums/open-discussion/trixbox-phones-home
http://voipsa.org/pipermail/voipsec_voipsa.org/2007-December/002533.html
http://voipsa.org/pipermail/voipsec_voipsa.org/2007-December/002528.html
http://voipsa.org/pipermail/voipsec_voipsa.org/2007-December/002522.html