The IMAP daemon (IMAPD32.EXE) in Ipswitch Collaboration Suite (ICS) allows remote attackers to cause a denial of service (CPU consumption) via an LSUB command with a large number of null characters, which causes an infinite loop.
http://www.securityfocus.com/bid/13727
http://www.ipswitch.com/support/imail/releases/imail_professional/im82hf2.html
http://www.idefense.com/application/poi/display?id=245&type=vulnerabilities