BoletimSec•October 23, 2026•🇵🇹Translated from Portuguese

Hirudo Android Banking Trojan Uninstalls Legitimate Bank Apps and Installs Attacker-Controlled Fakes

Researchers at ThreatFabric have published a detailed analysis of Hirudo, an Android banking trojan that doubles as a remote access tool and stealthily replaces legitimate bank applications with attacker-controlled copies.

The infection begins with lure applications themed around shopping, adult video content, and short video series. The identified decoys include Shopora, 1V1 X, ZoyaTV, and KoiShort. These apps first check whether Hirudo is already present on the device; if it is not, they display a fake update notification that leads the user to install a second package containing the trojan.

Once active, Hirudo leverages the accessibility service to monitor the device. Upon detecting a targeted banking application, it verifies the app’s signing certificate, presents a fraudulent update message, and opens the system uninstaller for the genuine app. Because Android refuses to treat the malicious copy as an update of an app signed by the bank, the original must be removed first. Users can interrupt the attack at this stage by cancelling the uninstallation or refusing the subsequent installation.

The replacement application carries the same package name and version number but is signed with a publicly known test key. After installation, an interception engine built on the open-source projects YAHFA and Dobby performs several evasion and bypass functions: it returns the bank’s legitimate certificate when the app queries its own signature, reports an empty list of accessibility services, removes the flag that prevents screen capture, and forwards selected Play Integrity checks to the operator’s command-and-control server.

The current toolkit contains eight pre-built replicas aimed at seven banks in Indonesia. Credential-harvesting operations target users in China, India, Mexico, Morocco, and Thailand. No infections have been reported in Brazil, and the fake payment overlay displays branding from a Malaysian bank.

Server records obtained by ThreatFabric in August 2026 contained thousands of stolen credentials, device identifiers, and financial profiles. The company notes that the attestation key set used in the scheme was publicly leaked and that at least two certificates from the set appear on Google’s revocation list.

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