Ransomware Research
S4b Ransomware
S4b is a malicious ransomware strain that encrypts victim files and demands ransom payment for decryption. First observed in the wild on September 1, 2023, this ransomware has been actively targeting systems worldwide.
Quick Facts
- Ransomware Family
- S4b
- First Seen
- September 1, 2023
How S4b Ransomware Works
Targeted Files
Full extension -> .id[C63F241F-3449].[submarine@cyberfear.com].s4b
File Encryption Patterns
S4b modifies encrypted files using specific patterns to mark them as encrypted:
File extensions added after encryption:
..s4bRansom Note and Payment Demands
After encrypting files, S4b displays ransom notes demanding payment for file recovery:
info.htaRansom message:
notes/info.hta
Note locations:
RootDiscsDesktopinfo.txtRansom message:
notes/info.txt
Note locations:
RootDiscsDesktopTechnical Indicators
Associated Executable Files
The following executable files are associated with S4b ransomware:
Backup.exe
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About This Analysis
This S4b 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 S4b.
Last updated: July 30, 2025