Ipswitch WS_FTP Server Manager before 6.1.1, and possibly other Ipswitch products, allows remote attackers to bypass authentication and read logs via a logLogout action to FTPLogServer/login.asp followed by a request to FTPLogServer/LogViewer.asp with the localhostnull account name.
http://www.vupen.com/english/advisories/2008/0473
http://www.securityfocus.com/bid/27654
http://www.securityfocus.com/archive/1/487697/100/200/threaded
http://www.securityfocus.com/archive/1/487686/100/200/threaded
http://securityreason.com/securityalert/4799