A new Android malware known as MasterFred uses fake login overlays to steal the credit card information of Netflix, Instagram, and Twitter users.
This new Android banking trojan also targets bank customers with custom fake login overlays in multiple languages.
A MasterFred sample was first submitted to VirusTotal in June 2021 and was first spotted in June. Malware analyst Alberto Segura also shared online a second sample one week ago, pointing out that it was used against Android users from Poland and Turkey.
After analyzing the new malware, Avast Threat Labs researchers discovered APIs provided by the built-in Android Accessibility service to display the malicious overlays.
“By utilizing the Application Accessibility toolkit installed on Android by default, the attacker is able to use the application to implement the Overlay attack to trick the user into entering credit card information for fake account breaches on both Netflix and Twitter,” Avast said.
The malicious use of the Accessibility service is not something new since malware creators have been using it to simulate taps and navigate the Android UI install their payloads, download and install other malware, and execute various operations in the background.
It seems there is an undetected Android #Banker affecting Turkey and Poland..
— Alberto Segura (@alberto__segura) November 3, 2021
However, some things make MasterFred stand out. One of them is that the malicious apps used to deliver the malware on Android devices also bundle the HTML overlays used to display the fake login forms and harvest the victims’ financial info.
The malware also uses the Onion.ws dark web gateway (aka Tor2Web proxy) to deliver the stolen information to Tor network servers under its operator’s control.
Since at least one of the malicious apps bundling the MasterFred banker was recently available in Google’s Play Store, it’s safe to say that MasterFred’s operators are also likely using third-party stores as a delivery channel for this new malware.
“We can say that at least one application was delivered via Google play. We believe that it has been removed already,” Avast’s research team told BleepingComputer.
Indicators of compromise (IOCs), including MasterFred sample hashes and command-and-control server domains, can be found in Avast Threat Labs’ Twitter thread.