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.