Rook
Intelligence Profile
According to PCrisk, Rook is ransomware (an updated variant of Babuk) that prevents victims from accessing/opening files by encrypting them. It also modifies filenames and creates a text file/ransom note ("HowToRestoreYourFiles.txt"). Rook renames files by appending the ".Rook" extension. For example, it renames "1.jpg" to "1.jpg.Rook", "2.jpg" to "2.jpg.Rook".
Threat Analysis
Rook is a high-sophistication threat actor of undetermined national origin, engaged in cyber operations with a primary motivation of financial.
Financially motivated threat actors like Rook prioritize monetary gain through methods such as ransomware deployment, banking trojans, cryptocurrency theft, BEC scams, or credential harvesting for resale on underground markets.
With high sophistication, Rook is capable of targeted intrusions using adapted commodity tools alongside custom implants, maintaining operational security and evading standard detection mechanisms.