The IM Server (aka IMserve or IMserver) 2.0.5.30 and probably earlier in Ipswitch Instant Messaging before 2.07 in Ipswitch Collaboration Suite (ICS) allows remote attackers to cause a denial of service (daemon crash) via certain data to TCP port 5179 that overwrites a destructor, as reachable by the (1) DoAttachVideoSender, (2) DoAttachVideoReceiver, (3) DoAttachAudioSender, and (4) DoAttachAudioReceiver functions.
http://www.vupen.com/english/advisories/2007/2621
http://www.securitytracker.com/id?1018440
http://www.securityfocus.com/bid/25031
http://www.ipswitch.com/support/instant_messaging/patch-upgrades.asp
http://secunia.com/advisories/26154
http://labs.idefense.com/intelligence/vulnerabilities/display.php?id=566