Re: Buffer Overflow Help

From: Erlend J. Leiknes (nookieat_private)
Date: Tue Jul 30 2002 - 10:33:12 PDT

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    You could try www.pulltheplug.com
    its a war-game where you will write buffer overflow exploits
    
    
    
    Leonard Leblanc wrote:
    > Hello All,
    > 
    > I am trying to experience buffer overflows first hand. I have glanced at a
    > number of articles and have decided to focus on "Smashing the Stack for Fun
    > and Profit" from Phrack Issue 49. I am trying out the examples from the text
    > and when I get to example 3 (which is the first real overflow example) it
    > doesn't quite work and I'm having a little trouble figuring it out.
    > 
    > The following example should bypass the "x=1" statement and print the
    > original value of "x" which is 0 (zero). Here's the code.
    > 
    > -=-=-=-=-=-=-=-=-=-=-=-=-=
    > void function(int a, int b, int c) {
    >   char buffer1[5];
    >   char buffer2[10];
    >   int *ret;
    > 
    >   ret = buffer1 + 12;
    >   (*ret) += 8;
    > }
    > 
    > void main() {
    >   int x;
    > 
    >   x=0;
    >   function(1,2,3);
    >   x=1;
    >   printf("%d\n",x);
    > }
    > -=-=-=-=-=-=-=-=-=-=-=-=
    > 
    > When I compile and execute this code it displays one and exits. I have tryed
    > this on RedHat 7.3 and Debian 2.2r6, both giving me the same result. Does
    > anyone have any insight into why this wouldn't work? After looking into the
    > assembly behind it, I think it has something to do with the "word size", but
    > can't seem to find any information as to what the "word size" is in Debian
    > or RedHat.
    > 
    > Any and All comments/suggestions are more than welcome. Also if anyone knows
    > of some other good text files/documents that talk about buffer overflows I
    > would be happy to receive links.
    > 
    > Leonard Leblanc
    > 
    > 
    > 
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    > 
    > 
    
    
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