Ransomware Research

Upsilon Ransomware

Upsilon is a malicious ransomware strain that encrypts victim files and demands ransom payment for decryption. First observed in the wild on January 1, 2023, this ransomware has been actively targeting systems worldwide.

Quick facts

Ransomware Family
Upsilon
First Seen
January 1, 2023

How Upsilon ransomware works

File encryption patterns

Upsilon modifies encrypted files using specific patterns to mark them as encrypted:

Extensions added after encryption
.upsil0n

Ransom note and payment demands

After encrypting files, Upsilon displays ransom notes demanding payment for file recovery:

fileUpsilon.txt
notes/Upsilon.txt
Location: EveryFolder

Technical indicators

Associated executable files

The following executable files are associated with Upsilon ransomware:

About this analysis

This Upsilon 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 Upsilon.

Last updated: December 30, 2025

Detection coverage

Elastio detects Upsilon inside your data and backups.

The Hunt Engine uses Deep File Inspection to identify Upsilon 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.

See How the Hunt Engine WorksRequest a Demo

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