Ransomware Research

Phobos-SDK Ransomware

Phobos-SDK is a malicious ransomware strain that encrypts victim files and demands ransom payment for decryption. First observed in the wild on April 1, 2023, this ransomware has been actively targeting systems worldwide. Security researchers also track this malware under the aliases: SDK.

Quick facts

Ransomware Family
Phobos-SDK
First Seen
April 1, 2023
Known Aliases
SDK

How Phobos-SDK ransomware works

File encryption patterns

Phobos-SDK modifies encrypted files using specific patterns to mark them as encrypted:

Extensions added after encryption
.SDK

Ransom note and payment demands

After encrypting files, Phobos-SDK displays ransom notes demanding payment for file recovery:

fileinfo.hta
notes/info.hta
Location: RootDiscs, Desktop
fileinfo.txt
notes/info.txt
Location: RootDiscs, Desktop

Technical indicators

Associated executable files

The following executable files are associated with Phobos-SDK ransomware:

About this analysis

This Phobos-SDK 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 Phobos-SDK.

Last updated: December 30, 2025

Detection coverage

Elastio detects Phobos-SDK inside your data and backups.

The Hunt Engine uses Deep File Inspection to identify Phobos-SDK 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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