A screen recording application that had amassed more than 50,000 downloads in Google Play was trojanized via an update last year, cybersecurity firm ESET reports.
The application, ‘iRecorder – Screen Recorder’, was initially published on Google Play in September 2021, without malicious functionality. When updated to version 1.3.8 in August last year, the AhMyth-based remote access trojan called AhRat was injected into the app.
According to ESET, the AhRat trojan, which has not been observed in the wild elsewhere, can record audio using the microphone and exfiltrate the recordings and other files from the infected devices, suggesting its use in an espionage campaign.
AhMyth is a cross-platform RAT previously used by APT36, a Pakistan-linked state-sponsored threat actor also known as Transparent Tribe and Mythic Leopard, but the AhRat observed in this incident could not be linked to any known advanced persistent threat (APT) actor.
The first malicious version of iRecorder, however, contained unmodified parts of AhMyth RAT’s malicious code. The second version contained the customized AhRat code, ESET says.
Both versions included only a limited set of malicious features compared to AhMyth RAT, which can exfiltrate call logs, contacts, and messages, send messages, track the device location, obtain a list of files on the device, record audio, and take photos.
Because it provided video recording capabilities, iRecorder had the necessary permissions to record audio and access files on the device, allowing the malware to function without issue.
Based on commands received from its command-and-control (C&C) server, the malware could exfiltrate audio and video files, documents, web pages, and archive files.
“While it is possible that the app developer had intended to build up a user base before compromising their Android devices through an update or that a malicious actor introduced this change in the app; so far, we have no evidence for either of these hypotheses,” ESET concludes.
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