Serv-U up to 5.2 Denial of Service

[Patrick <patrickthomassen () gmail com>]

Serv-U FTP server is a secure, advanced FTP server for Windows. However, like most programs, it is not completely 
bugfree.

I (and maybe more people with me) found this bug some time ago. It can be triggered as *every* user that can log in, 
anonymous included, and exists in possibly every version. (At least 4.x and 5.x series).

The exploit might be a cliché but it might threaten (hosting and other) companies that use this FTP server.

Following commands will trigger the crash:

STOU COM1
STOU LPT1
STOU PRN
STOU AUX

However, "STOU NUL" does NOT work.

Greetings,
Patrick