ESET researchers, thanks to a tweet announcing a discovery of what was thought to be Android banking malware, discovered a ransomware operation targeting Android users in Canada.
Using two COVID-19-themed websites, the attackers behind the operation lured people to download a ransomware app disguised as an official COVID-19 tracing tool. Now, both websites are down. ESET researchers wrote a decryption tool for CryCryptor’s victims, based on a bug in the malicious app.
“CryCryptor contains a bug in its code that allows any app installed on the affected device to launch any service provided by the buggy app. So we created an app that launches the decrypting functionality built into CryCryptor. Clearly, the operation using CryCryptor was designed to piggyback on the official COVID-19 tracing app.” explains Lukáš Štefanko, who conducted the research.
The targeting of the ransomware operation, including its timing, coincides with the announcement by the Canadian government of the intention to back the development of a nationwide, voluntary tracing app to be called COVID Alert.
With the malicious websites down, security vendors aware, and the decryptor available, this app no longer poses a threat. However, this is true only for one particular version of CryCryptor.
CryCryptor is based on an open source code. “We notified GitHub, where the code is hosted, but they don’t have an excellent track record in taking down malicious projects,” comments Štefanko.
ESET products provide protection against the CryCryptor ransomware, detecting it as Android/CryCryptor.A.
“Besides using a quality mobile security solution, we advise Android users to install apps only from reputable sources such as the Google Play store,” concludes Štefanko.
