Budget Android device models that are counterfeit versions associated with popular smartphone brands contain multiple hidden trojans designed to target WhatsApp and WhatsApp Business messaging app.
Doctor Web first came across the malware in July 2022. It was discovered in the system partition of at least four different smartphones: radmi note 8, P48pro, Note30u, and Mate40.
The cybersecurity firm published a report earlier this week. It stated: “These incidents are united by the fact that the attacked devices were copycats of famous brand-name models.”
“Moreover, instead of having one of the latest OS versions installed on them with the corresponding information displayed in the device details (for example, Android 10), they had the long outdated 4.4.2 version.”
The tampering concerns two files, “/system/lib/libcutils.so” and “/system/lib/libmtd.so”, that are modified specifically so that when the libcutils.so system library is used by any app, it triggers the execution of a trojan incorporated in libmtd.so.
If the apps using said libraries are WhatsApp or WhatsApp Business, libmtd.so proceeds to launch a third backdoor which downloads and installs additional plugins from a remote server onto the compromised devices.
“The danger of the discovered backdoors and the modules they download is that they operate in such a way that they actually become part of the targeted apps.”
“As a result, they gain access to the attacked apps’ files and can read chats, send spam, intercept and listen to phone calls, and execute other malicious actions, depending on the functionality of the downloaded modules,” the researchers added.
Conversely, if the app using the libraries turns out to be wpa_supplicant (system daemon that’s used to manage network connections) libmtd.so is configured to start a local server which allows connections from a remote or local client via the “mysh” console.
The cybersecurity specialists theorised that the system partition implants could be part of the FakeUpdates (or SocGolish, as it is sometimes known) malware family based on the discovery of another trojan embedded into the system application responsible for over-the-air (OTA) firmware updates.
The malicious app is engineered to exfiltrate detailed metadata about the infected device. It also downloads and installs other software without user knowledge via Lua scripts.
It is recommended that users purchase mobile devices from official stores and legitimate distributors to reduce these risks.
