Wednesday, July 29, 2009

5th SMS Ransomware Variant Offered for Sale

"Your system has been blocked because it is running a pirated copy of Windows. In order to unblock it, enter the activation code sent to you by SMS-ing the following number."

Demand and emerging business models based on micro-payment ransom meet supply, with yet another SMS-based ransomware variant offered for sale ($25). Just like in previous underground market propositions, this one comes with a value-added service in the form of managed undetected binaries on a daily basis for an extra $5 for an undetected copy. It's worth pointing out that due to the customization offered, their original layouts and the error messages will look a lot different once their customers get hold of the ransomware.

Key features include:
- protecting against repeated infection through Mutex
- pops-up on the top of all windows
- disables safe mode, as well as possible key combinations attempting to bypass the window
- adds itself as a trusted executable/excluded one in Windows Firewall
- variety of non-intrusive auto-starting/executable injecting capabilities
- Rotx encryption for the activation codes
- ability to embedd more than one activation code
- monitors and automatically blocks process names of tools that could allow removal
- complete removal of the code from the system once the correct activation code is entered
- zero detection rate of a sampled binary -- of course the advertiser is biased and he didn't bother including reference to the service he used (Virustotal, etc.)

Despite several isolated cases where the originally Russian-based ransomware is affecting international English-speaking users, the campaigns are primarily targeting Russian speaking users -- at least for the time being until the malware authors or their customers start localizing it. This emerging micro-payment ransomware business model is the direct result of largely unregulated market segments allowing literally anyone to get hold of a premium and automatically managed number in order to facilitate it.

Related posts:
4th SMS Ransomware Variant Offered for Sale
3rd SMS Ransomware Variant Offered for Sale
SMS Ransomware Source Code Now Offered for Sale
New ransomware locks PCs, demands premium SMS for removal

This post has been reproduced from Dancho Danchev's blog.