Zimperium

Android Ransomware Mantax Otax Encrypts Files and Streams Victim Screen in Real Time

Researchers at Zimperium have identified a new Android ransomware strain called Mantax Otax that combines file encryption with live screen recording and surveillance capabilities. The malware is distributed through sideloaded APK files delivered via messaging apps and phishing messages rather than official app stores. Once installed, it uses AES encryption to lock files with the .enc extension and conducts ransom negotiations directly on the infected device through an on-screen chat interface. In addition to encryption, Mantax Otax continuously captures the screen, saves footage as MP4 video, and streams it to operators while also photographing the surroundings with the device camera. The malware abuses accessibility services to read on-screen content, intercepts SMS messages to steal two-factor authentication codes, and exfiltrates contacts, call logs, browser history, and credentials from WhatsApp and Telegram. It also displays a fake lock screen to capture the device PIN. Impact is reduced on Android 10 and later due to Scoped Storage restrictions, though surveillance functions remain active. Evidence points to a targeted campaign against users in Indonesia.