Ransomware Research

CryLock Ransomware

CryLock is a malicious ransomware strain that encrypts victim files and demands ransom payment for decryption. First observed in the wild on April 1, 2020, this ransomware has been actively targeting systems worldwide.

Quick facts

Ransomware Family
CryLock
First Seen
April 1, 2020

How CryLock ransomware works

File encryption patterns

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

Extensions added after encryption
./\[reddragon3335799@protonmail\.ch\]\[sel3\]\.\[[0-9A-F]{8}-[0-9A-F]{8}\]$/./\[flydragon@mailfence\.com\]\[sel1ru\]\.\[[0-9A-F]{8}-[0-9A-F]{8}\]$/./\[hopeandhonest@smime\.ninja\]\.\[[A-F0-9]{8}-[A-F0-9]{8}\]$/.nbf

Ransom note and payment demands

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

filehow_to_decrypt.hta
notes/how_to_decrypt.hta
Location: EveryFolder

Technical indicators

Associated executable files

The following executable files are associated with CryLock ransomware:

About this analysis

This CryLock 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 CryLock.

Last updated: December 30, 2025

Detection coverage

Elastio detects CryLock inside your data and backups.

The Hunt Engine uses Deep File Inspection to identify CryLock 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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What is CryLock Ransomware? | Elastio