Ransomware Research
Guster Ransomware
Guster is a malicious ransomware strain that encrypts victim files and demands ransom payment for decryption. First observed in the wild on December 1, 2016, this ransomware has been actively targeting systems worldwide.
Quick Facts
- Ransomware Family
- Guster
- First Seen
- December 1, 2016
How Guster Ransomware Works
File Encryption Patterns
Guster modifies encrypted files using specific patterns to mark them as encrypted:
File extensions added after encryption:
..lockedRansom Note and Payment Demands
After encrypting files, Guster displays ransom notes demanding payment for file recovery:
Instructions_HERE!.txtRansom message:
notes/Instructions_HERE!.txt
Note locations:
DesktopRansom message:
notes/note.txt
Note locations:
OnceOnCompletionTechnical Indicators
Associated Executable Files
The following executable files are associated with Guster ransomware:
Guster.exeGuster (32).exe
Elastio Can Help You
Don't let Guster ransomware take over your data
Elastio provides advanced ransomware protection and recovery solutions to keep your organization safe.
About This Analysis
This Guster ransomware analysis is part of Elastio's comprehensive ransomware detection database. Elastio provides advanced ransomware protection and recovery solutions, helping organizations defend against and recover from ransomware attacks like Guster.
Last updated: July 30, 2025