Ransomware Research
Zyklon Ransomware
Zyklon is a malicious ransomware strain that encrypts victim files and demands ransom payment for decryption. First observed in the wild on May 1, 2016, this ransomware has been actively targeting systems worldwide.
Quick Facts
- Ransomware Family
- Zyklon
- First Seen
- May 1, 2016
How Zyklon Ransomware Works
Targeted Files
https://www.acronis.com/en-us/blog/posts/serpent-pretends-be-octopus-new-step-zyklon-ransomware-evolution/ https://www.hybrid-analysis.com/sample/61764600d8fb7f84d6f578a72b409aa7dd7f1c3fb5705fb2792d8459e87726f2?environmentId=100 Protected with ConfuserEx Requires C&C
File Encryption Patterns
Zyklon modifies encrypted files using specific patterns to mark them as encrypted:
File extensions added after encryption:
..zyklon
..srpx
Ransom Note and Payment Demands
After encrypting files, Zyklon displays ransom notes demanding payment for file recovery:
/\bREADME_TO_RESTORE_FILES_[A-Za-z0-9]{3}\.html\b/
Ransom message:
notes/README_TO_RESTORE_FILES_o6W.html
Note locations:
UserFolders
RootDiscs
/\bREADME_TO_RESTORE_FILES_[A-Za-z0-9]{3}\.txt\b/
Ransom message:
notes/README_TO_RESTORE_FILES_o6W.txt
Note locations:
UserFolders
RootDiscs
Technical Indicators
Associated Executable Files
The following executable files are associated with Zyklon ransomware:
Octopus
6612683490_2604543229_download.zp.exe
Serpent.exe
urlref_http185.183.99.24update.zp
update.zp
Elastio Can Help You
Don't let Zyklon ransomware take over your data
Elastio provides advanced ransomware protection and recovery solutions to keep your organization safe.
About This Analysis
This Zyklon 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 Zyklon.
Last updated: July 30, 2025