We are all aware that patching is very important. Many websites, however, take the risk of not updating their software for various reasons: it requires manual modifications, adjustment of the current code to work with the changes, the layout gets broken... In other words- they are lazy.
Knowing this, cybercriminals try their luck and brute force many websites in hopes of hitting the unpatched ones.
If you happen to find a new module in your outdated Joomla installation called "mod_404" or "mod_modules"- you are probably a victim of the following attack, which started a few weeks ago.
This attack was divided into several stages:
Following the initial infection (using one of several patched Joomla vulnerabilities)the cybercriminals attempt to expand the attack by searching for other websites hosted on the same webserver in order to inject them with an IFRAME which redirects to the following obfuscated PHP script:
Snippet obfuscated PHP script
After several iterations of eval, readable PHP code is revealed:
Snippet d-obfuscated PHP script
The script does several things which aren't particularly noteworthy, up to the point where it accesses the page"hxxp://wsouser.ru/iframe1.txt" to receive an updated URL which is added into JavaScript code that is sent to the victim:
Snippet JavaScript code
The code collects basic information about the user's browser,ensures it's the first visit of the victim to the site, and loads yet another IFRAME from a different URL.
Snippet PHP script
The script "red_one_f5.php" loads a different file,"iframe2.txt", to receive the next hop of the attack. This iframe redirects the browser to "hxxp://belkabelka.in/?id=red", which hosts a TDS (Traffic Distribution System) named "Keitaro TDS".
Since the TDS is configurable, the cybercriminal can redirect the traffic to any URL in order to avoid detection by security vendors, in this case the traffic is redirect to the Neutrino Exploit Kit.
It's important to note that the Joomla CMS is a very popular system. There are almost 2 million websites which use the Joomla platform and so it makes sense that many of these websites that don't keep their systems up-to-date will remain vulnerable to such automated attacks.
This isn't a lone case of its kind- other than the many hops taken on the way to the payload, there is nothing particularly sophisticated or challenging here, and that is perhaps the most troubling part about it. This is yet another reminder that these techniques are not gone from the world- they are still here; and probably hereto stay. Please keep that in mind and keep your web applications up-to-date!
Written by Anat Davidi and Daniel Chechik
