Vuln Dev
understanding buffer overflows Oct 31 2007 02:36PM
secacc7 hotmail com (3 replies)
hello, my name is michael, im from austria - so my english is very bad.

A few days ago i begin to experiment with bufferoverflows in linux.

i wrote a little c++ programm like this:

#include <string.h>

void main()

{

char buffer[10];

char COPY[]="AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA...";

strcpy((char *)buffer,(char *)COPY);

}

k, this works very well, i got a core dump and have startet gdb. but in the output from "info all" was eip not overwritten

so i put a few lines in the program to output addresses from functions and variables.

addresses from functions where over 0 (eg (dec)500000) and addresses from vars under 0 (eg -5000000)

i think this is maybe the problem - but why?

output from gdb:

eax 0x0 0

ecx 0x41414141 1094795585

edx 0x1d7 471

ebx 0xb7e27ff4 -1209892876

esp 0x4141413d 0x4141413d

ebp 0x41414141 0x41414141

esi 0xb7f77ce0 -1208517408

edi 0x0 0

eip 0x80484ad 0x80484ad

eflags 0x210286 [ PF SF IF RF ID ]

cs 0x73 115

ss 0x7b 123

ds 0x7b 123

es 0x7b 123

fs 0x0 0

gs 0x33 51

hope anybody can help me understand/learn.

greets from austria, michael

[ reply ]
Re: understanding buffer overflows Nov 05 2007 04:53PM
Chris Eagle (cseagle redshift com)
Re: understanding buffer overflows Nov 03 2007 01:12PM
Ben Petering (bjp dfmagicp org)
Re: understanding buffer overflows Nov 01 2007 12:39PM
3APA3A (3APA3A SECURITY NNOV RU)


 

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