NB65 Ransomware
NB65 is a malicious ransomware strain that encrypts victim files and demands ransom payment for decryption. First observed in the wild on April 1, 2022, this ransomware has been actively targeting systems worldwide. Security researchers also track this malware under the aliases: ContiStolen.
Quick facts
How NB65 ransomware works
File encryption patterns
NB65 modifies encrypted files using specific patterns to mark them as encrypted:
Ransom note and payment demands
After encrypting files, NB65 displays ransom notes demanding payment for file recovery:
notes/R3ADM3.txt
About this analysis
This NB65 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 NB65.
Last updated: December 30, 2025
Elastio detects NB65 inside your data and backups.
The Hunt Engine uses Deep File Inspection to identify NB65 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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