Ransomware scumbags have widened their net with a new software nasty that infects Android smartphones and tablets.
The Koler-A ransomware trojan is delivered automatically to peeps browsing malicious pornographic sites; it poses as a media player offering access to premium content.
Koler-A requires the user to enable side-loading and manually install the application, so it could be argued the malware mostly preys on the foolish using basic social-engineering trickery.
It does not use software vulnerabilities to install itself automatically, or other more advanced techniques.
Once installed, the trojan launches a browser on top of the home screen and briefly displays a logo of the player it impersonates. Meanwhile, in the background, an Android application package file (APK) calls home to one of the 200+ domains known to be involved in the scam and transmits the compromised device’s IMEI in the process, as well as a key that appears to be identical for all infections.
Victims are confronted with an HTML page localised in the victim’s language. The Trojan then disables the back button, but still lets users briefly return to the home screen. After arriving at the home screen, users have five seconds to uninstall the APK before a timer brings the malicious application back to the foreground. This goes on every five seconds in an annoying move designed to coax marks into paying a ransom of $300 to restore their device to normal.
Victims are falsely accused of attempting to view banned pornography (child pornography/zoophilia/rape, etc.) as well as committing copyright violations via a pop up message that is adjusted by country to make reference to national laws and police organisations.
Unlike the latest generation of PC ransomware nasties, no attempt is made to encrypt content on compromised devices – despite claims to the contrary by cybercrooks.
Thankfully, the Koler-A malware is easily removed.
"Koler-A can be easily removed by either pressing the home screen and navigating to the app, then dragging it on the top of the screen where the uninstall control is located, or by booting the device in safe mode and then uninstalling the app,” explained Catalin Cosoi, chief security strategies at Romanian security software firm Bitdefender. “Although the message claims the stored data is encrypted, the application does not have the permissions it needs to touch files; it’s a lie to push users into paying the ransom.”
Koler functionality is very limited but the APK code is highly obfuscated, possibly as a precaution against the possibility that other criminals might take the code and use it to build their own nasty. Bitdefender reckons that the prolific gang behind the Reveton / IcePol fake cop trojan on Windows PCs may be behind the scam.
“The Android version of Icepol might be a test run for cyber-criminals to see how well this type of scam can be monetised on mobile platforms,” Cosoi concluded. “If this is the case, we should expect much more sophisticated strains of ransomware, possibly capable of encrypting files, to emerge shortly.”
Bitdefender reckons that the prolific gang behind the Reveton / IcePol fake cop Trojan on Windows PCs may be behind the scam. "It's not only the [fake warning] messages, but also the "suggested" payment forms that users are faced with when payment is requested," BitDefenders's Cosoi explained. Like Icepol before it the Android ransomware requests payment in either Ukash and Moneypack.
It's unclear how many people have been hit by the ransomware.®