The Bamital web-search-hijacking botnet has been taken down by security researchers from Microsoft and Symantec with help from the Feds. The crack unit raided a number of data centres where the botnet's servers were located.
Bamital malware intercepted victims' search requests - including those sent to Google, Yahoo! and Microsoft's Bing - and redirected them to websites touting dodgy software and scams, netting the crooks running the botnet revenue from the fraud.
More than eight million Windows-powered computers have been attacked by Bamital over the last two years, according to security researchers at Microsoft and Symantec. Bamital is a Trojan that infects only Windows machines and is distributed under the guise of a useful software app. It's also been known to appear as the payload of drive-by download attacks from compromised websites. Once installed, the Trojan modifies search results on compromised computers.
For example, Microsoft investigators found that Bamital rerouted a search for "Nickelodeon" to a website that distributed spyware. In another case, a search for Norton Internet Security was redirected to a rogue antivirus site that distributes malware.
The takedown operation severed the cybercriminals' ability to manipulate and control Bamital-infected computers by seizing internet resources associated with the scam. As with previous botnet take-down operations, this involved combined legal and technical operations. Based on findings from security research, Microsoft filed a lawsuit against the botnet's operators seeking an order to pull the plug on the zombie network. The court granted Microsoft’s request and on 6 February, Microsoft – escorted by the US Marshals Service – seized servers associated with controlling the botnet from web-hosting facilities in Virginia and New Jersey.
Prior to the takedown users of infected machines might have been unaware that anything was wrong, but they will now find that their search function is broken as their search queries will consistently fail. Owners of infected computers trying to complete a search query will now be redirected to an official Microsoft and Symantec webpage explaining the problem and provides information and resources to remove the Bamital infection and other malware from their computers.
Something broadly similar occurred when the Feds had to set up temporary clean DNS servers for months following the case of the DNSChanger takedown operation in November 2011. But since Bamital was restricted to hijacking search results rather than every internet lookup, the logistics of running a clean-up are simpler.
The clean-up procedure will make it much more difficult for the unknown crooks behind Bamital to rebuild their operation.
The Bamital takedown, known as Operation b58, is the sixth botnet disruption operation in three years carried out by Microsoft as part of its Project MARS (Microsoft Active Response for Security) and the second done in cooperation with Symantec. More details on the operation can be found in a blog post by Richard Domigues Boscovich, assistant general counsel at Microsoft Digital Crimes Unit, here.
An animated video illustrating how cybercriminals used Bamital malware to hijack search results and commit click fraud from Symantec can be found here. It's informative - but the cheesy background music is truly dire. ®