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Re: Overflowing Scripts fail to work
From: Bill Weiss <houdini+pen-test () clanspum net>
Date: Mon, 24 Apr 2006 04:56:26 +0000

Paul Sebastian Ziegler(psz () observed de)@Sat, Apr 22, 2006 at 10:30:43AM +0200:
Hallo list!

I've been on this for quite some time and after failing to find out
anything on the Internet I've finally decided to propose this question
here. Any help would be greatly appreciated!

Due to interest I have started to try to understand
buffer-overflow-attacks. The theory is fine with me. But now I'm getting
quite some trouble when trying to write exploiting scripts.

Let me show you what I mean:
(code and example runs cut)

Using your C code and the same python code:

(%:~/tmp)- ./a.out `python -c "print 'A' * 524"`
AAAAAAA (lots of As cut)
a.out: stack smashing attack in function main()
zsh: abort      ./a.out `python -c "print 'A' * 524"`
(%:~/tmp)- python
Python 2.4.2 (#1, Oct 16 2005, 00:06:10)
[GCC 3.3.6 (Gentoo Hardened 3.3.6, ssp-3.3.6-1.0, pie-8.7.8)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
import os
os.system("./a.out " + ("A" * 524))
AAAAAAA (again, lots of As)
a.out: stack smashing attack in function main()
6

(%:~/tmp)- python vuln.py
AAAAAAA (As galore)
a.out: stack smashing attack in function main()
(%:~/tmp)

Gentoo with kernel 2.6.12-gentoo-r10, GCC 3.3.6 (Gentoo Hardened 3.3.6,
ssp-3.3.6-1.0, pie-8.7.8), Python 2.4.2 built with this GCC.

The Hardened stuff is why I'm seeing "stack smashing attack", but I can't
imagine why this would be causing a failure where yours isn't (while
running from within python).

Unless the newer kernels added something here (which I doubt), it should
be working for you.  We're on almost the same build.

-- 
Bill Weiss

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