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
How S4b ransomware works
File encryption patterns
S4b modifies encrypted files using specific patterns to mark them as encrypted:
Ransom note and payment demands
After encrypting files, S4b displays ransom notes demanding payment for file recovery:
notes/info.hta
notes/info.txt
Technical indicators
Associated executable files
The following executable files are associated with S4b ransomware:
- Backup.exe
About this analysis
This S4b 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 S4b.
Last updated: December 30, 2025
Elastio detects S4b inside your data and backups.
The Hunt Engine uses Deep File Inspection to identify S4b 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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