*[email protected]*.ws

[Content by Gemini 2.5]

This document provides a comprehensive overview of the ransomware variant identified by the file extension *[email protected]*.ws, which is part of the prolific STOP/Djvu ransomware family. It covers technical aspects, prevention, and recovery strategies to help individuals and organizations combat this threat.

Technical Breakdown:

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: The exact file extension used by this specific ransomware variant is .ws. This extension is appended to encrypted files.
  • Renaming Convention: The ransomware follows the typical STOP/Djvu renaming convention. For an original file named document.docx, the encrypted version would be renamed to something like:
    document.docx.[uniqueID][email protected]
    or more commonly:
    document.docx.[random_4_char_string].ws
    The .[uniqueID][email protected] part is often an embedded string that includes a unique victim ID and the contact email address for the attackers, followed by the final .ws extension. The _readme.txt ransom note usually contains the full contact email ([email protected]) and possibly the victim’s unique ID.

2. Detection & Outbreak Timeline

  • Approximate Start Date/Period: The STOP/Djvu ransomware family, to which this variant belongs, has been highly active since late 2017/early 2018. New variants with different file extensions and contact emails are released frequently. The *[email protected]*.ws variant would have emerged within this ongoing wave of activity, likely in late 2023 or early 2024, given the common practice of attackers frequently changing contact details and extensions to evade detection and tracking. It signifies a recent iteration of the well-established Djvu strain.

3. Primary Attack Vectors

The STOP/Djvu ransomware primarily relies on social engineering and deceptive distribution methods rather than exploiting network vulnerabilities for initial access. Its main propagation mechanisms include:

  • Cracked Software & Illegal Downloads (Warez): This is the most prevalent infection vector. Users download compromised software installers, keygens, software cracks, and pirated media (movies, games, music) from torrent sites, free download portals, and file-sharing networks. These files are Trojanized to contain the ransomware payload.
  • Malicious Websites & Drive-by Downloads: Visiting compromised or malicious websites can sometimes lead to an infection if the site automatically downloads a malicious file that the user is tricked into executing.
  • Fake Software Updates: Pop-ups or alerts promoting fake updates for legitimate software (e.g., Adobe Flash Player, Java, web browsers) can deliver the ransomware.
  • Bundled with Adware/Potentially Unwanted Programs (PUPs): The ransomware might be included as a secondary payload in seemingly legitimate but ad-supported or unwanted software installations.
  • Phishing Campaigns (Less Common for Djvu): While not the primary method for Djvu, email attachments (e.g., seemingly legitimate invoices, shipping notifications, or resumes containing malicious macros or embedded scripts) can also deliver the payload. However, Djvu is more commonly spread via direct user interaction with malicious downloads.
  • No Exploitation of Network Vulnerabilities (Typically): Unlike some enterprise-targeting ransomware, STOP/Djvu variants like *[email protected]*.ws typically do not leverage vulnerabilities like EternalBlue (SMBv1 exploits) or brute-force Remote Desktop Protocol (RDP) connections for initial infection. They rely on user execution.

Remediation & Recovery Strategies:

1. Prevention

Proactive measures are crucial to mitigate the risk of *[email protected]*.ws infection:

  • Regular, Offline Backups: Implement a robust backup strategy. Store critical data on external drives or cloud services that are disconnected from the network once the backup is complete. This ensures that even if ransomware encrypts your system, your data remains safe.
  • Avoid Pirated Software: Never download or use cracked software, keygens, or activators from unofficial sources. This is the primary vector for STOP/Djvu infections.
  • Keep Software and OS Updated: Apply security patches and updates for your operating system (Windows, macOS) and all installed software (browsers, plugins, antivirus, etc.) promptly.
  • Use Reputable Antivirus/Anti-Malware Software: Install and maintain a comprehensive security suite with real-time protection and behavioral detection capabilities. Keep its definitions up to date.
  • Enable Firewalls: Ensure your operating system’s firewall and/or a dedicated network firewall are active to control network traffic.
  • User Education: Train users about the dangers of phishing emails, suspicious links, and untrusted downloads. Emphasize caution when interacting with files from unknown sources.
  • Disable Unnecessary Services: Turn off services like Remote Desktop Protocol (RDP) if not actively needed. If RDP is required, secure it with strong, unique passwords, multi-factor authentication (MFA), and restrict access to trusted IPs only.

2. Removal

If your system is infected, follow these steps to remove *[email protected]*.ws:

  • Isolate the Infected System: Immediately disconnect the infected computer from the network (unplug Ethernet cable, disable Wi-Fi) to prevent the ransomware from spreading to other devices on the network.
  • Identify and Terminate Malicious Processes:
    • Open Task Manager (Ctrl+Shift+Esc).
    • Look for suspicious processes with unusual names or high CPU/memory usage. Research any unfamiliar processes.
    • End the process tree for identified malicious executables.
  • Boot into Safe Mode: Restart your computer in Safe Mode with Networking. This often prevents the ransomware from fully loading, making removal easier.
  • Scan with Multiple Anti-Malware Tools:
    • Download and run reputable anti-malware scanners such as Malwarebytes, SpyHunter, ESET, or Bitdefender. These tools are often effective at detecting and removing STOP/Djvu ransomware.
    • Perform a full system scan.
  • Remove Detected Files and Registry Entries: Allow the anti-malware software to quarantine and delete all detected malicious files and associated registry entries.
  • Check for Persistent Mechanisms:
    • Review msconfig (Startup tab) or Task Manager (Startup tab) for suspicious programs set to run at boot.
    • Check Task Scheduler for new, unusual scheduled tasks created by the ransomware.
    • Examine common ransomware persistence locations (e.g., %APPDATA%, %TEMP%).
  • Delete Ransom Note: Remove the _readme.txt file (and any other ransom notes) from all affected directories.
  • Crucial Note: Info-Stealer Presence: A significant characteristic of STOP/Djvu variants is that they often deploy information-stealing malware (e.g., Vidar Stealer, RedLine Stealer, Azorult) prior to or alongside file encryption. This means your login credentials, cryptocurrency wallets, browser data, system information, and other sensitive personal data may have already been exfiltrated. A thorough scan for these secondary infections is critical.

3. File Decryption & Recovery

  • Recovery Feasibility: The possibility of decrypting files encrypted by *[email protected]*.ws largely depends on the encryption key used:
    • Online Keys: If the ransomware successfully communicated with its command-and-control (C2) server during encryption, it used a unique “online key” specific to your infection. Files encrypted with online keys are generally not decryptable without the specific private key, which is held by the attackers.
    • Offline Keys: If the ransomware failed to connect to its C2 server, it might have used a hardcoded “offline key.” Researchers sometimes manage to recover these offline keys, allowing for decryption.
    • Paying the Ransom is Not Recommended: There is no guarantee you will receive a working decryption key, and it encourages further criminal activity.
  • Essential Tools/Patches:
    • Emsisoft Decryptor for STOP/Djvu: This is the primary tool for decrypting files affected by STOP/Djvu ransomware. You can download it from Emsisoft’s official website. It works by checking for known offline keys or attempting to decrypt files if you can provide a pair of original (unencrypted) and encrypted files for analysis. It’s often updated as new offline keys are discovered.
    • Shadow Volume Copies (VSS): The ransomware typically attempts to delete Shadow Volume Copies using commands like vssadmin.exe Delete Shadows /All /Quiet. However, in some cases, it might fail or only partially succeed. Check if previous versions of your files are available via Windows’ “Previous Versions” tab in file properties.
    • Data Recovery Software: Tools like PhotoRec, Recuva, or R-Studio can sometimes recover the original, unencrypted files that the ransomware deleted after creating encrypted copies. Success rates vary and decrease significantly with continued system use.
    • Backups: The most reliable method of recovery is restoring data from clean, offline backups.

4. Other Critical Information

  • Additional Precautions:
    • Information Stealer Threat: As mentioned, the presence of information-stealing malware (like Vidar, RedLine, Azorult) is a hallmark of STOP/Djvu. Assume your credentials (passwords, banking details, crypto wallet keys, browser history) have been compromised.
    • Password Reset: Immediately change all passwords for critical online accounts (email, banking, social media, cloud services) that were accessed from the infected machine. Use strong, unique passwords and enable Multi-Factor Authentication (MFA) wherever possible.
    • Financial Monitoring: Monitor your bank accounts, credit card statements, and cryptocurrency wallets for any suspicious activity.
    • Notify Affected Parties: If sensitive personal data was on the infected machine, consider notifying relevant parties (e.g., financial institutions, employers, clients) if required by data breach notification laws.
  • Broader Impact:
    • Widespread Impact on Individuals: Due to its reliance on common user behaviors (downloading pirated content), STOP/Djvu affects a very large number of individual users and small businesses, often leading to significant personal data loss and financial strain if no backups are available.
    • High Volume of Variants: The constant emergence of new file extensions and contact emails makes it challenging for antivirus vendors to maintain signature-based detection and for researchers to keep up with offline key recovery.
    • Beyond Encryption: The dual threat of file encryption and information theft makes STOP/Djvu one of the most insidious and damaging ransomware families for the average user, extending the impact beyond just data availability to identity theft and financial fraud.