Ransomware Research
Sigrun Ransomware
Sigrun is a malicious ransomware strain that encrypts victim files and demands ransom payment for decryption. First observed in the wild on May 1, 2018, this ransomware has been actively targeting systems worldwide.
Quick Facts
- Ransomware Family
- Sigrun
- First Seen
- May 1, 2018
How Sigrun Ransomware Works
File Encryption Patterns
Sigrun modifies encrypted files using specific patterns to mark them as encrypted:
File extensions added after encryption:
..sigrun
Ransom Note and Payment Demands
After encrypting files, Sigrun displays ransom notes demanding payment for file recovery:
RESTORE-SIGRUN.txt
Ransom message:
notes/RESTORE-SIGRUN.txt
Note locations:
EveryFolder
RESTORE-SIGRUN.html
Ransom message:
notes/RESTORE-SIGRUN.html
Note locations:
EveryFolder
Technical Indicators
Associated Executable Files
The following executable files are associated with Sigrun ransomware:
5.exe
sigrun.exe
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About This Analysis
This Sigrun 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 Sigrun.
Last updated: July 30, 2025