The other day a worm, often referred to as “Error Check System” was spreading on Facebook.  In fact if you searched for information on this threat, your search results were poisoned to lead unsuspecting victims to a site that attempts to install a rogue anti-spyware Trojan.  Some folks blogged that this search connection was “too much of a coincidence“, and that the Facebook part of the threat was a “red herring“.  I do not believe this is the case, and here’s why.

Last week I was following up on a comment made to the McAfee Avert Labs blog.  The URL provided by the visitor (**********.******.bee.pl/waledac_botnet.html) redirected to another site that attempted to install the same trojan.  Running a search on part of that URL yielded hundreds of search results, many that were placed high up on Google’s results.  The summary text was relevant for the search term and it’s clear that those behind the redirects are manipulating the internet (Google); by not only getting their newly created sites to appear high on the search results page, but also to display relevant text in the page summary section, and for the hottest terms.  Here’s one example, ironically related to the recent Gmail outage.

 

You’ll also notice that the page summary is identical to the top search result, taken from Google News.  Looking at more search results it is clear that the attackers are targeting popular search terms.

 Other searches show the results using all lowercase titles, the same as used by Google Trends.  In fact, checking some of the top Google Trends links we can see that the abusers are hitting it (ash wednesday 2009 was the #1 search term at the time of this writing, this is image was edited to fit on the blog).

The notion of malware distributors abusing Google Trends is not new, and received some attention in October of last year.  However, I do not recall previous attacks being as aggressive as the current ones, being distributed across numerous sites, targeting many many high-profile search terms, and having the poisoned links regularly appearing high up in the result pages.

Once a user visits one of these poisoned links, the destination page references a script file (style.js), which is obfuscated.

Decoding the script shows that it redirects the user based on the referring URL being “google”,”msn”,”yahoo”,” comcast”,”aol.com”.  This is just one of the many ways the bad guys focus their attacks on potential victims, while making it a tiny bit more difficult for others to discover it.  Once you’re redirected, it’s situation normal for the attackers, various fake alert and scanning messages and windows appearing, ultimately leading to the installation of a FakeAlert trojan (such as one of the 9,500+ known binaries identified by McAfee as FakeAlert-AB).

If you made it down to the bottom of this blog, I probably don’t need to remind you to look carefully before you click, on the Web.