Ransomware Research
Rook Ransomware
Rook is a malicious ransomware strain that encrypts victim files and demands ransom payment for decryption. First observed in the wild on November 1, 2021, this ransomware has been actively targeting systems worldwide.
Quick Facts
- Ransomware Family
- Rook
- First Seen
- November 1, 2021
How Rook Ransomware Works
Targeted Files
https://www.sentinelone.com/labs/new-rook-ransomware-feeds-off-the-code-of-babuk/ 16 bytes stripes encryption Encrypts first 0x180000 bytes
File Encryption Patterns
Rook modifies encrypted files using specific patterns to mark them as encrypted:
File extensions added after encryption:
..RookRansom Note and Payment Demands
After encrypting files, Rook displays ransom notes demanding payment for file recovery:
HowToRestoreYourFiles.txtRansom message:
notes/HowToRestoreYourFiles.txt
Note locations:
EveryFolderTechnical Indicators
Associated Executable Files
The following executable files are associated with Rook ransomware:
J4PAZ.exe
Elastio Can Help You
Don't let Rook ransomware take over your data
Elastio provides advanced ransomware protection and recovery solutions to keep your organization safe.
About This Analysis
This Rook ransomware analysis is part of Elastio's comprehensive ransomware detection database. Elastio provides advanced ransomware protection and recovery solutions, helping organizations defend against and recover from ransomware attacks like Rook.
Last updated: July 30, 2025