Most people would have a hard time imagining life without their mobile phone, but a new variant of the Koler Android ransomware is not only infecting devices via SMS, but also effectively holding them hostage until victims pay up.

According to HackerNews, those responsible for the attacks are trying to get consumers to click on a link that they are distributing via text message. The link launches the Koler Android ransomware as a type of SMS worm. Adaptive Mobile researchers were among the first to notice and raise awareness about the attacks.

Experts told SC Magazine that the hackers are demanding around $300 once a device has been compromised by showing the user a pop-up screen via a photo-viewing app. Unfortunately, it doesn’t end there: Even as consumers consider whether to make a payment using MoneyPak, the Koler Android ransomware will spread through the smartphone’s contact list, sending a message that says, “someone made a profile of [contact name] and he uploaded some of your photos! is that you?” along with the link.

An article on PCAdvisor says the window that the Koler Android ransomware opens up to cover the entire screen is designed to look as though it came from a law enforcement agency such as the FBI. It accuses the user of viewing child pornography (or storing it) and positions the ransom demand as a “fine.”

This particular variant of the Koler Android ransomware borrows techniques from Selfmite and other SMS worms, according to Adaptive Mobile. Besides using text messages, the social-engineering trick of tapping into someone’s address book makes it more likely that other victims will click through, particularly since the message is only sent once in order to appear natural.

Hundreds are expected to have been affected by the attacks in just the first day, TechWorld reported, with approximately 75 percent of the known incidents taking place in the United States. Because the URL goes to a Dropbox page, Adaptive Mobile was able to ask the cloud-based storage firm to deactivate the embedded link. However, it wouldn’t be difficult for the attackers to simply change where the link is hosted.

Though its use of SMS and Dropbox may be novel, the Koler Android ransomware may not turn out to have the same impact as Selfmite, which was discovered in June and reportedly sent thousands of dangerous text messages across some 16 countries. Even if the attackers don’t get money from their victims, these types of attacks can prove to be expensive for smartphone users who don’t have SMS as part of their data plan.

Either way, consumers using Android devices may want to be particularly careful about how they treat messages, even from people they know — especially if they contain a vague-looking link within them.

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