Ransomware Research

BigLock Ransomware

BigLock is a malicious ransomware strain that encrypts victim files and demands ransom payment for decryption. First observed in the wild on May 1, 2020, this ransomware has been actively targeting systems worldwide. Security researchers also track this malware under the aliases: CoronaLock, Corona-lock, CoronaLocker.

Quick Facts

Ransomware Family
BigLock
First Seen
May 1, 2020
Known Aliases
CoronaLockCorona-lockCoronaLocker

How BigLock Ransomware Works

Targeted Files

Encrypts first 0x75300 bytes Requires C&C -> fbb2a672cd40b979add8f52e4cba8f58273160b687913ab83f650ae3681efa25 -> http://195.189.96.66/repeater.php

File Encryption Patterns

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

File extensions added after encryption:

..biglock..corona-lock..pandemic..systems32x..nermer..t1000..t800

Ransom Note and Payment Demands

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

fileREADME_LOCK.TXT

Ransom message:

notes/README_LOCK.TXT

Note locations:

Desktop
filePROTECT.txt
file@_FILES_WERE_ENCRYPTED_@.TXT

Ransom message:

notes/@_FILES_WERE_ENCRYPTED_@.TXT

Note locations:

EveryFolder
file@_HOW_TO_DECRYPT_FILES_@.TXT

Ransom message:

notes/@_HOW_TO_DECRYPT_FILES_@.TXT

Note locations:

EveryFolder
file@_HOW_TO_PAY_THE_RANSOM_@.TXT

Ransom message:

notes/@_HOW_TO_PAY_THE_RANSOM_@.TXT

Note locations:

EveryFolder
filePROTECT_INFO.TXT

Ransom message:

notes/PROTECT_INFO.TXT

Note locations:

Desktop
fileCRYPTiNFO.TXT

Ransom message:

notes/CRYPTiNFO.TXT

Note locations:

Desktop
file!!!HOW_TO_DECRYPT!!!.txt

Technical Indicators

Associated Executable Files

The following executable files are associated with BigLock ransomware:

  • 2020-05-22_17-36-19.exe
  • covidworldcry.exe
  • DUMo
  • setup_theme_895670451.bin
  • lkx333.exe
  • convimage.exe
  • locker.exe
  • drvintel.exe
  • SysLogsService.exe
  • cmd.exe

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About This Analysis

This BigLock 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 BigLock.

Last updated: July 30, 2025

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