BuLock Ransomware
BuLock is a malicious ransomware strain that encrypts victim files and demands ransom payment for decryption. First observed in the wild on December 1, 2023, this ransomware has been actively targeting systems worldwide.
Quick facts
How BuLock ransomware works
File encryption patterns
BuLock modifies encrypted files using specific patterns to mark them as encrypted:
Ransom note and payment demands
After encrypting files, BuLock displays ransom notes demanding payment for file recovery:
notes/HOW_TO_BACK_FILES.html
Technical indicators
Associated executable files
The following executable files are associated with BuLock ransomware:
- svhost.exe
About this analysis
This BuLock 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 BuLock.
Last updated: December 30, 2025
Elastio detects BuLock inside your data and backups.
The Hunt Engine uses Deep File Inspection to identify BuLock 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.
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