Multiple methods exist that allow for a crash of the Serv-U FTP server versions 4.x through 5.x.
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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