Perhaps timed to coincide with Todd Phillips’ highly rated film exploring the Joker’s origin story, a piece of malware named “Joker” was identified in two dozen Android applications that, until recently, were available in the Google Play Store. The malware sneakily signs its victims up for subscription services that incur periodic fees, fees that users may not catch unless they carefully review credit card bills. quotes a cybersecurity expert describing the capabilities of this clever caper as follows:

“For example, in Denmark, Joker can silently sign the victim up for a 50 DKK/week service (roughly ~6,71 EUR). This strategy works by automating the necessary interaction with the premium offer’s webpage, entering the operator’s offer code, then waiting for a SMS message with a confirmation code and extracting it using regular expressions. Finally, the Joker submits the extracted code to the offer’s webpage, in order to authorize the premium subscription.” 

Remarkably, the infected apps, which are listed in the Lifehacker post, were downloaded more than 470,000 times before Google put a stop to the swindling software.

So remember, inclusion in the Google Play Store or Apple’s App Store and an innocent-sounding name like “Beach Camera,” “Reward Clean,” or “Spark Wallpaper,” is no guarantee that the app is safe. Just like clicking on links in emails, downloading apps from unknown providers is done at your own risk. If you do download apps, please remember to carefully review your credit card bills more than once a year, or you might be exclaiming “Holy Trickery, Batman!” at belatedly discovering that you’ve been paying 50 DKK/week throughout 2019 for a subscription to a site in Denmark. (50 DKK/week is approximately $7.15 US/week)

Check out our series, Privacy Perils, to learn what steps you can take to guard your personal and company data. For more information about this topic and other cyber security concerns, please contact a member of our Privacy & Data Security team.