A new Facebook Worm exploits multiple cloud services

Pierluigi Paganini March 13, 2015

Security Experts at Malwarebytes security firm spotted a new  Facebook worm that spreads itself by leveraging multiple cloud services.

Social media are a privileged attack vector, recent reports published by the principal security firms confirm that cyber criminal are exploiting these platforms for illegal activities. Last disastrous news for the users of the popular social network Facebook is related to the spread of Facebook worm belonging to the Kilim malware family that could recruit victim’s PC as zombie of a botnet.

According to a report published by Malwarebytes firm, the attack chain starts with a message on the social network that proposes scandalous sex photos of teenagers, a very dangerous lure.

The message includes a shortened ow.ly link that drives victims to another URL, which leads to victims to an Amazon Web Services (AWS) page. But that’s not all, because the number of redirections continues, the Amazon Web Services (AWS) page in fact leads victims to a malicious website (videomasars.healthcare), that is used by crooks to verify the platform used by the victim, desktop computer or mobile device, and redirects them to different path depending on their machine.

Mobile users are redirected to affiliate pages that contain various offers, meanwhile users using desktop computers are asked to download a file from a Box folder that contain the malware. The file pretends to offer a collection of Videos (Videos_New.mp4_2942281629029.exe), but executing a scan via VirusTotal is possible to verify its malicious nature (Rate 30 / 57 at the time I’m writing). The malicious file is a downloader for the Facebook worm, which comes in a form of Chrome extension, and additional binaries.

Facebook worm social network malwarebytes-13032015

The researchers confirmed that the Facebook work also creates a shortcut for Chrome that actually launches a malicious app in the browser directly to the Facebook website.

“As mentioned earlier, a rogue Chrome extension is injected but that is not all. The malware also creates a shortcut for Chrome that actually launches a malicious app in the browser directly to the Facebook website:” is reported in the blog post published by MalwareBytes. “In this ‘modified’ browser, attackers have full control to capture all user activity but also to restrict certain features,”  For example, they have disabled the extensions page that once can normally access by typing chrome://extensions/, possibly in an attempt to not let the user disable or remove the malicious extension.”

Last part of the attack consists in the spread of the Facebook worm among the victims’ Facebook friends, by sending the lure message. Malwarebytes has already reported the various URLs to their respective owners, some of them have already shutdown malicious links.

As usual, I suggest you to carefully inspect any link, specially the shortened URL, before clicking on it.

Pierluigi Paganini

(Security Affairs –  Facebook worm, social network)

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