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Ransomware group profile · #230 by claimed victims

Rook ransomware

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.

Active First seen Dec 2021
9Victims claimed on leak sites
0Victims in the last 30 days
0Victims in the last 90 days
1Countries hit
1Leak-site URLs tracked, 0 online
8 Jan 2022Latest claim recorded

Victimology

Who Rook claims to have breached, from 9 leak-site posts recorded by VULONE.

Claims per month last 12 months

Dec 2025: 0DecJan 2026: 0Feb 2026: 0Mar 2026: 0MarApr 2026: 0May 2026: 0Jun 2026: 0JunJul 2026: 0Aug 2026: 0Sep 2026: 0SepOct 2026: 0Nov 2026: 0

Top sectors

Manufacturing2
Technology2
Healthcare1
Professional Services1
Energy & Utilities1
Retail & E-Commerce1

Top countries

Japan1

Latest claimed victims 9 most recent

VictimSectorCountryClaimed
Abdi ibrahim Healthcare - 8 Jan 2022
Evalueserve Professional Services - 28 Dec 2021
DENSO denso.com Manufacturing JP 28 Dec 2021
Data breach summary Not Found - 26 Dec 2021
Rossell Techsys(Data will be given tomorrow) Technology - 18 Dec 2021
KMG Prestige, Inc. (Data will be given tomorrow) kmg prestige, inc. (data will be given tomorrow) Energy & Utilities - 18 Dec 2021
Rosendahl Design Group Retail & E-Commerce - 14 Dec 2021
Rossell Techsys Technology - 14 Dec 2021
KMG Prestige, Inc. kmg prestige, inc. Manufacturing - 7 Dec 2021

All 9 Rook victims, searchable

Full victim list with claim posts, domains, timing and exports, plus the negotiation chats and leak-site screenshots VULONE archives for this crew.

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Tactics, techniques and procedures

ATT&CK technique mapping for Rook is in progress. Victimology, infrastructure status and leak-site tracking are live above.

Indicators, detections and the full playbook

Hashes, C2 addresses, onion services, Sigma and YARA detections per technique, and the negotiation transcripts are available to signed-in analysts.

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Frequently asked

Is Rook ransomware still active?
Rook is tracked as active. The most recent leak-site claim VULONE recorded is dated 8 January 2022.
How many victims has Rook claimed?
VULONE has recorded 9 leak-site victim claims attributed to Rook since December 2021, across 1 countries and 7 sectors.
Which industries does Rook target?
The sectors most often named on the Rook leak site are Manufacturing, Technology, Healthcare.
Which countries are most affected by Rook?
Most Rook victims recorded by VULONE are located in Japan.
Where does VULONE get Rook victim data?
Claims are collected continuously from the group's own leak sites and cross-checked with ransomware.live and RansomLook. A claim is the group's assertion, not a confirmed breach.

VULONE research mentioning Rook

Other ransomware groups

Victim claims are collected from leak sites and enrichment partners (ransomware.live, RansomLook) and represent the group's own assertions, not confirmed breaches. Profile last updated 31 October 2026. Questions or corrections: research@vulone.com.