A new backdoor malware called ‘Wpeeper’ has been detected circulating in at least two unofficial app stores that mimic the popular Uptodown App Store. Discovered by the XLab team at QAX on April 18, 2024, Wpeeper utilizes a unique method by leveraging compromised WordPress sites to serve as intermediate relays for its command and control (C2) servers. This technique helps the malware maintain a low profile and evade detection by both security professionals and automated systems. The analysis began when the team encountered an unfamiliar ELF file embedded within Android package files (APKs), which showed zero detections on VirusTotal.
The operation of Wpeeper is particularly sophisticated due to its encrypted and dynamically updatable C2 communication system. The malware sends commands through AES encrypted channels, and these commands are signed with an elliptic curve signature to safeguard against unauthorized access. If any of the WordPress sites acting as relays are cleaned up or taken down, Wpeeper is capable of receiving new server addresses to update its list of command sources, ensuring continuous control over the infected devices.
Wpeeper’s functionality is extensive and harmful, with capabilities to steal a wide array of sensitive data from the infected devices. It can retrieve detailed information about the device, list all installed applications, download files, and execute commands directly on the device. The malware’s commands include updating the malware, deleting itself, and running arbitrary shell commands, which makes it highly versatile and dangerous.
Given the stealthy and robust design of Wpeeper, coupled with its unknown motives and operators, the threat it poses is significant. Potential risks include identity theft, financial fraud, network infiltration, and intelligence collection. To protect against such risks, it is advised to only install applications from Android’s official Google Play store and ensure that the device’s built-in anti-malware tool, Play Protect, is active. This situation underscores the ongoing threats posed by malware and the importance of maintaining strict cybersecurity practices when downloading and installing applications.
