OSEC

Neohapsis is currently accepting applications for employment. For more information, please visit our website www.neohapsis.com or email hr@neohapsis.com
3COM TFTPD Overflow: SEH Overwrite

jeremy.jungingergmail.com
Date: Fri Jan 25 2008 - 08:58:43 CST


I'm attempting to exploit an already known bug in 3COM TFTPD server, and execute "calc.exe" with my shellcode. I have control of ECX/EIP, and can overwrite both SEH and pointer to next SEH successfully, and have used:

Pointer to next SEH: \xeb\x10\x90\x90
SEH: \x69\x12\xab\x71 (POP/POP/RET in ws2_32.dll)

A full writeup with screenshots is available at:
http://filebin.ca/pmuwqm/SEHOverwrite.rtf

I'm getting "Debugged program was unable to process exception", so I hit shift+f9 (in olly) and it terminates with some strange exit code. Could you take a peek and see what I'm missing here?

Thanks guys!

-jj