According to this post at CA's Security Advisor Research Blog, the malware, Win32/RansomSMS.AH, comes bundled with software named uFast Download Manager. The software is installed without any indication to the user, and (shocker here) the uninstaller does not work.
CA provided a screen shot of an infected system, which appears to be a Windows XP box, but no indication in their post what other operating systems could be affected.
Here's the ransom note, as translated by CA:
CA claims to have created an activation code generator, to help users regain their Internet access.
Internet access is blocked due to violation of the license agreement schedules of uFast Download Manager You must activate your copy Get a registration code by sending an SMS with the following code fw0004199 to number 7122
In response you will receive an activation message. Enter the activation message received from the SMS response ________
It's not a wild guess to expect much more online criminal activity like this during the holiday season, so be careful where you browse and what you download.
Here's a recent post on the rising threat of Rogueware.
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