Ransomware Research

JSWorm Ransomware

JSWorm is a malicious ransomware strain that encrypts victim files and demands ransom payment for decryption. First observed in the wild on April 1, 2019, this ransomware has been actively targeting systems worldwide. Security researchers also track this malware under the aliases: JSWorm, JSWorm 2.0, JSWorm 3.0-3.1, JSWorm 4.0.2-4.0.3.

Quick Facts

Ransomware Family
JSWorm
First Seen
April 1, 2019
Known Aliases
JSWormJSWorm 2.0JSWorm 3.0-3.1JSWorm 4.0.2-4.0.3

How JSWorm Ransomware Works

Targeted Files

Encrypts first 0x27100 kb Full extension of encrypted files -> .[ID-XXXXXXXXX][MAIL].JSWORM https://www.bleepingcomputer.com/forums/t/700990/jsworm-ransomware-jsworm-jurasik-jswrm-support-topic/

File Encryption Patterns

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

File extensions added after encryption:

..JSWORM..JURASIK..JSWRM..UNNAMED..TRUMP

Ransom Note and Payment Demands

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

fileJSWORM-DECRYPT.html

Ransom message:

notes/JSWORM-DECRYPT.html

Note locations:

EveryFolder
fileUNNAMED-DECRYPT.txt

Ransom message:

notes/UNNAMED-DECRYPT.txt

Note locations:

EveryFolder
fileJSWORM-DECRYPT.txt

Ransom message:

notes/JSWORM-DECRYPT.txt

Note locations:

EveryFolder
fileJSWORM-DECRYPT.hta
fileJSWRM-DECRYPT.hta

Ransom message:

notes/JSWRM-DECRYPT.hta

Note locations:

EveryFolder
fileTRUMP-DECRYPT.txt

Ransom message:

notes/TRUMP-DECRYPT.txt

Note locations:

EveryFolder
file31NSXXX-DECRYPT.hta
fileJBUIIGF-DECRYPT.hta

Ransom message:

notes/JBUIIGF-DECRYPT.txt

Technical Indicators

Associated Executable Files

The following executable files are associated with JSWorm ransomware:

  • JSWorm.exe
  • build.exe
  • MANWARD6
  • MANWARD6.exe
  • 5527.exe
  • jsworm.exe
  • svchost.exe

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About This Analysis

This JSWorm 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 JSWorm.

Last updated: July 30, 2025

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