A newly identified Android banking trojan called Hirudo is taking an unusually aggressive approach to evading mobile security: instead of merely overlaying fake login screens on top of legitimate apps, it replaces the victim’s banking app with a modified copy. According to mobile security firm ThreatFabric, the malware retains nearly all of the original app’s code but injects a hooking engine based on the open-source frameworks YAHFA and Dobby. That lets it operate inside the banking app’s own process, effectively turning the app’s defenses against it.
Hirudo is typically delivered through seemingly useful apps, including a shopping app called Shopora, an adult-content app named 1V1 X, and short-drama apps such as ZoyaTV and KoiShort. These loader apps provide the functionality users expect, then display a fake “update” notification that leads to permission requests—most importantly access to Android’s Accessibility services. Once granted, Hirudo can uninstall the genuine banking app, download a patched version, and install it automatically using its elevated permissions.
The replacement app is designed to defeat several common security checks. It can substitute the genuine signing certificate when queried, hide enabled Accessibility services, remove screenshot protection, alter key-attestation certificates, and route Play Integrity requests through an attacker-controlled server. By doing so, it can make a tampered banking app appear legitimate to both the user and parts of the device’s security system. Researchers note that the process is risky for the attacker because the victim can interrupt the app replacement at two separate points.
Once active, Hirudo gives operators extensive control over the infected phone. It can steal banking passwords, payment PINs, device-unlock credentials, and SMS messages; stream the screen in real time; capture screenshots; record audio; and access both cameras. The malware also uses fake checkout pages to collect payment PINs and then shows a fabricated payment-success message, making victims believe a transaction completed normally while their data is being harvested.
ThreatFabric says Hirudo has impersonated at least seven Indonesian banks, with additional targeting observed in China, India, Mexico, Morocco, and Thailand. An unsecured backend panel linked to the operation contained thousands of application-credential entries, along with device, lock-screen, and financial-profile data, though the total number of victims remains unknown. The researchers recommend that banks validate integrity and attestation server-side, tie those checks to sessions and protected actions, and maintain behavioral and transaction-risk controls. Android users should keep devices updated, avoid installing APKs from unofficial stores, and periodically run Google Play Protect scans.
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