New variants of an Android ransomware family have surged over the past six months to some 600 unique versions.
That's a dramatic jump from the 100 variants created between October to the start of December, says Michael Covington, vice president of product strategy for Wandera, which published new data on the ransomware today.
The new strains of the mobile ransomware use a range of disguises to avoid detection. The SLocker variations are repackaged as altered icon, for example, or offer unique resources and executable files. SLocker encrypts images, documents, and videos, as well as blocks access to the device before demanding payment to unlock the phone and its contents.
Chief security officers and their teams have reason to worry about the rapid rise in the number of SLocker strains, say security experts. The malware has morphed beyond just locking users' screens on their Android devices and demanding payment, to taking over administrative rights and controlling the device, including its microphone, speakers, and the camera.
Bogdan Botezatu, senior e-threat analyst with Bitdefender, says an Android smartphone infected with SLocker could potentially broadcast highly sensitive information presented during a closed-door boardroom meeting without the user's knowledge, for example.
Wandera's Covington points to potential risks to sales and consulting staff, for example. "In a lot of situations where the employees work out in the field like in sales or consulting, it can have a massive impact on their business if they are locked out of their phone and data," he explains.
Victim organizations paid an estimated $10 million in ransom to unlock confidential data stored on Android phones that fell victim to SLocker, according to Wandera's report.
By the Numbers
Android ransomware first emerged in 2014, after creators of the Reveton/IcePol ransomware for PCs turned their attention to Android devices and cooked up the Android.Trojan. Koler.A and then later Android.Trojan.SLocker, according to Bitdefender's Botezatu.
For the first two years, SLocker was among the top 20 Android malware families and then shot up to the top 10 in 2016, notes Botezatu. "Its rise to the top 10 was mostly because of the frustration factor. It's a psychological thing when people can't get information from their smartphone," he says. "People were willing to pay the ransom. The mobile device is more personal than the personal computer."
But now SLocker ranks in the No. 14 to No. 18 spot among the top 20 Android malware families, as cyberthieves create new types of Android malware and enlarge the pool of contenders and dilute SLocker's influence, Botezatu says.