Description

According to Cisco Talos, Interlock, a new ransomware group, is targeting industries including US healthcare, IT, and government. Interlock employs big-game hunting and double extortion tactics, stealing and threatening to release sensitive data unless a ransom is paid. Worldwide Secrets Blog is a data leak site where the group publishes stolen data and offers victims live chat support. Interlock’s attack chain typically spans 17 days, beginning with unauthorized access via a fake Google Chrome browser updater. This delivers a remote access tool (RAT), which collects system data, establishes a connection to a command-and-control (C2) server, and steals credentials. Furthermore, the RAT disables Endpoint Detection and Response (EDR) and deletes event logs in order to evade detection. Lateral movement is achieved via Remote Desktop Protocol (RDP) and other tools, potentially including Linux systems. The ransomware encrypts both Windows and Linux systems using variants of LibTomCrypt. The encryption uses Cipher Block Chaining (CBC) for Windows, while Linux systems may use either CBC or RSA encryption. Interlock avoids critical system folders to prevent instability. In addition, Talos noted similarities between Interlock and Rhysida, including shared tools and attack methods, suggesting a connection. Organizations are advised to improve security hygiene by updating software, using multi-factor authentication, and securing RDP access to mitigate the risks of these attacks.