Buffer overflow in WS_FTP FTP Server 3.1.1 allows remote authenticated users to execute arbitrary code via a long SITE CPWD command.
http://www.securityfocus.com/bid/5427
http://www.iss.net/security_center/static/9794.php
http://www.ipswitch.com/Support/WS_FTP-Server/patch-upgrades.html
http://www.atstake.com/research/advisories/2002/a080802-1.txt