Ransomware Research

DOOK Ransomware

DOOK is a malicious ransomware strain that encrypts victim files and demands ransom payment for decryption. First observed in the wild on September 1, 2023, this ransomware has been actively targeting systems worldwide.

Quick Facts

Ransomware Family
DOOK
First Seen
September 1, 2023

How DOOK Ransomware Works

File Encryption Patterns

DOOK modifies encrypted files using specific patterns to mark them as encrypted:

File extensions added after encryption:

..DOOK

Ransom Note and Payment Demands

After encrypting files, DOOK displays ransom notes demanding payment for file recovery:

fileREADME!.txt

Ransom message:

notes/README!.txt

Note locations:

RootDiscsDesktop
fileInfo.hta

Ransom message:

notes/Info.hta

Note locations:

RoamingStartUp

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About This Analysis

This DOOK 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 DOOK.

Last updated: October 30, 2025

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