✅ Report Title: Beast Ransomware Analysis Report

✅ Executive Summary:

📌 What Is the Beast Ransomware

- Beast ransomware, first discovered in June 2025, gained significant attention after attacking three South Korean companies in February 2026.

- As a result of analyzing the posts of user "MNSTR," who promoted Beast ransomware, since this user has a history of promoting Monster ransomware in the past, Beast ransomware is judged to be a rebranding of Monster ransomware.

📌 TTPs (Tactics, Techniques, Procedures)

- According to SOCRadar, the Beast ransomware group is known to perform initial access through phishing emails and compromised RDP endpoints, and it has also been confirmed to access victim systems by utilizing leaked or stolen account information.

📌 Other Related Group

- As of March 2026, a total of six groups have been identified as using Beast ransomware or having associations due to overlaps in source code and ransom notes.

📌 Malware & Encryption

- All strings used in Beast ransomware are encrypted with XOR operations, and a total of 17 execution arguments are supported.

- Files targeted for encryption are encrypted using the X25519 + ChaCha20 algorithms, and if the “-z” execution argument is not activated, 160 bytes of metadata are added.

- If the “-z” execution argument is activated, the format of the file targeted for encryption is converted into a compressed file in the form of “encrypted file + ransom note.”

✅ Recommended Threat Detection and Mitigation Actions:

- Beast ransomware performs initial access through phishing emails and compromised RDP endpoints; therefore, mitigation measures such as detecting malicious attachments and URLs in emails, providing security awareness training for employees, and applying multi-factor authentication (MFA) to externally exposed RDP services are recommended.

🧑‍💻 Author: S2W TALON

👉 Contact us: https://s2w.inc/en/contact

*The full report is available upon request or with a subscription to the S2W platform.