source: http://www.securityfocus.com/bid/2508/info

A successfully logged-in user, via IMAP, could cause MDaemon to terminate the connection. If the user submits either a 'SELECT' or 'EXAMINE' command appended with 250 or more characters, MDaemon will refuse any new connections to the IMAP service. A restart of the service is required in order to gain normal functionality. 

* OK company.mail IMAP4rev1 MDaemon 3.5.6 ready

1 LOGIN JOE PASSWORD
* OK LOGIN completed
1 SELECT AAAAAAA....