New Android ransomware is being flogged through a spam campaign, researchers say.

The "Fake Defender” malware first discovered in June has been updated with a different ruse to target Android users, primarily in Russia.
The malicious application, detected as fakedefender.B, was designed to look like the official application for an adult video website, Symantec researcher Roberto Sponchioni said.
But once users install the app, messages warn them to run an antivirus scan that is supposedly Avast AV.
Once the spurious AV scan finished, the user's phone is locked for their “protection,” and the app asks for a ransom payment of $100 via a prepaid MoneyPak card.