Ransomware Research

BL4CK Locker Ransomware

BL4CK Locker is a malicious ransomware strain that encrypts victim files and demands ransom payment for decryption. First observed in the wild on June 1, 2025, this ransomware has been actively targeting systems worldwide.

Quick facts

Ransomware Family
BL4CK Locker
First Seen
June 1, 2025

How BL4CK Locker ransomware works

File encryption patterns

BL4CK Locker modifies encrypted files using specific patterns to mark them as encrypted:

Extensions added after encryption
.BL4CK

Ransom note and payment demands

After encrypting files, BL4CK Locker displays ransom notes demanding payment for file recovery:

message
notes/note.txt
Location: OnceOnCompletion

Technical indicators

Associated executable files

The following executable files are associated with BL4CK Locker ransomware:

About this analysis

This BL4CK Locker ransomware analysis is part of Elastio's comprehensive ransomware detection database. Elastio provides advanced ransomware protection and recovery, helping organizations defend against and recover from ransomware attacks like BL4CK Locker.

Last updated: December 30, 2025

Detection coverage

Elastio detects BL4CK Locker inside your data and backups.

The Hunt Engine uses Deep File Inspection to identify BL4CK Locker across live data, replicated data, and backups. If this family is in your environment, Elastio finds it before encryption completes. Run a scan against your recovery points to confirm.

See How the Hunt Engine WorksRequest a Demo

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