FilesL0cker Ransomware
FilesL0cker is a malicious ransomware strain that encrypts victim files and demands ransom payment for decryption. First observed in the wild on September 1, 2018, this ransomware has been actively targeting systems worldwide. Security researchers also track this malware under the aliases: FilesLocker v2.0.
Quick facts
How FilesL0cker ransomware works
File encryption patterns
FilesL0cker modifies encrypted files using specific patterns to mark them as encrypted:
Ransom note and payment demands
After encrypting files, FilesL0cker displays ransom notes demanding payment for file recovery:
notes/#解密我的文件#.txt
notes/#DECRYPT MY FILES#.txt
notes/note.txt
Technical indicators
Associated executable files
The following executable files are associated with FilesL0cker ransomware:
- Windows Update.exe
- fileslockerRansome.exe
- Installer.exe
- INSTALLER.EXE
- FilesLocker.exe
- csses3.exe
- csses.exe
- csses1.exe
- csses2.exe
- Sql49.exe
Recovery and decryption tools
Decryption tools may be available for FilesL0cker. Review the resources below:
About this analysis
This FilesL0cker 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 FilesL0cker.
Last updated: December 30, 2025
Elastio detects FilesL0cker inside your data and backups.
The Hunt Engine uses Deep File Inspection to identify FilesL0cker 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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