*[email protected]*.eth

[Content by Gemini 2.5]

This detailed resource is compiled to assist individuals and organizations in understanding, preventing, and recovering from the ransomware variant identified by the file extension *[email protected]*.eth. This variant belongs to the prolific STOP/Djvu ransomware family, which constantly updates its file extensions and encryption keys.

Technical Breakdown:

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: The exact file extension used by this variant is [email protected]. This string is appended to the original filename.
  • Renaming Convention: When a file is encrypted, its name is altered to include this extension. For example, a file named document.docx would be renamed to [email protected]. Similarly, photo.jpg would become [email protected]. All encrypted files will bear this specific suffix.
    Alongside encrypted files, the ransomware drops a ransom note typically named _readme.txt in every folder containing encrypted data.

2. Detection & Outbreak Timeline

  • Approximate Start Date/Period: The STOP/Djvu ransomware family has been continuously active since late 2018. New variants, identified by their unique file extensions and email contacts, are released frequently, sometimes daily. The [email protected] variant would be a relatively recent iteration, likely appearing in late 2023 or early 2024, indicating the ongoing evolution and persistence of this ransomware group.

3. Primary Attack Vectors

The STOP/Djvu ransomware family, including the [email protected] variant, primarily relies on less sophisticated but highly effective social engineering and deceptive distribution methods rather than complex network exploits. Its main propagation mechanisms include:

  • Cracked Software/Pirated Content: This is the most common infection vector. Users download and execute infected “cracked” versions of popular software, key generators, software activators, or game cheats from unofficial torrent sites, warez forums, or file-sharing platforms. The ransomware is bundled within these seemingly legitimate installers.
  • Malicious Downloads: Downloads from deceptive pop-up ads, fake software update prompts (e.g., for Flash Player), or untrustworthy download sites that host “free” software or utilities.
  • Adware Bundles: Sometimes distributed as part of adware bundles or malicious installers promoted through aggressive advertising.
  • Phishing Campaigns (Less Common but Possible): While not the primary method for STOP/Djvu, email attachments containing malicious scripts (e.g., JavaScript, VBScript) or documents with enabled macros could potentially lead to infection, though it’s more characteristic of other ransomware families.
  • Fake Websites/Typo-squatting: Users might be redirected to malicious websites disguised as legitimate ones, prompting them to download infected files.
  • No Network Propagation: Unlike ransomware like WannaCry or NotPetya, STOP/Djvu variants generally do not possess worm-like capabilities to spread across networks by exploiting vulnerabilities (e.g., EternalBlue, SMBv1). Infection typically occurs via direct execution on the targeted system, making it more of an endpoint threat than a network-spreading threat.

Remediation & Recovery Strategies:

1. Prevention

Proactive measures are the most effective defense against ransomware like *[email protected]*.eth:

  • Regular Backups: Implement a robust backup strategy following the 3-2-1 rule (3 copies of data, 2 different media types, 1 off-site). Offline or immutable backups are crucial as they cannot be encrypted by ransomware.
  • Software Updates & Patching: Keep your operating system, web browsers, antivirus software, and all applications fully updated. Patches often close security vulnerabilities that attackers could exploit.
  • Reputable Antivirus/Endpoint Detection and Response (EDR): Use a high-quality antivirus or EDR solution with real-time protection and behavioral analysis capabilities. Keep its definitions up-to-date.
  • Firewall Configuration: Properly configure your firewall to block unauthorized incoming and outgoing connections.
  • User Education: Educate users about the dangers of downloading cracked software, opening suspicious email attachments, clicking on dubious links, and the general risks of visiting untrustworthy websites.
  • Disable Macros by Default: Configure Microsoft Office to disable macros by default, or only allow digitally signed macros from trusted sources.
  • Strong, Unique Passwords & Multi-Factor Authentication (MFA): Protect accounts with strong, unique passwords, and enable MFA wherever possible, especially for critical services and remote access.
  • Ad-Blockers & Script Blockers: Consider using browser extensions that block malicious ads and scripts to reduce exposure to malvertising.

2. Removal

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

  1. Isolate the Infected System: Immediately disconnect the infected computer from the internet and any local networks (Wi-Fi, Ethernet). This prevents further spread to other devices and stops the ransomware from communicating with its command-and-control server.
  2. Identify and Terminate Malicious Processes:
    • Reboot the computer into Safe Mode with Networking. This loads only essential services, which can sometimes prevent the ransomware from fully executing.
    • Open Task Manager (Ctrl+Shift+Esc) and look for suspicious processes. Common names used by Djvu can be random strings of characters, or processes related to the initial “crack” or “keygen” that was run. End these processes if identified.
  3. Perform a Full System Scan:
    • Use a reputable anti-malware solution (e.g., Malwarebytes, SpyHunter, Kaspersky, Bitdefender, Microsoft Defender) to perform a deep, full system scan. Ensure the anti-malware software is up-to-date.
    • Allow the anti-malware program to quarantine or remove all detected threats.
  4. Check for Persistence Mechanisms:
    • Startup Programs: Use Task Manager (Startup tab) or MSConfig (System Configuration) to check for suspicious entries configured to run at startup. Disable or remove them.
    • Scheduled Tasks: Open Task Scheduler and look for newly created tasks that could re-launch the ransomware. Delete any suspicious ones.
    • Registry Entries: While more advanced, some variants create registry entries. If comfortable, you can check HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run and HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run for unusual entries.
    • Hosts File: The ransomware typically modifies the C:\Windows\System32\drivers\etc\hosts file to block access to security-related websites. Open it with Notepad and remove any new entries (lines with IP addresses like 127.0.0.1 followed by security domain names). Save the file.
  5. Delete Shadow Volume Copies: The ransomware attempts to delete Shadow Volume Copies (VSS) to prevent easy restoration. While this prevents a quick recovery, it’s good practice to run vssadmin delete shadows /all /quiet from an elevated Command Prompt after confirming the ransomware is gone, just to ensure no remnants are left. Note: This command will permanently delete all existing restore points, so only do this if you have no other recovery options and have confirmed the malware is removed.

3. File Decryption & Recovery

  • Recovery Feasibility: The feasibility of decrypting files encrypted by *[email protected]*.eth depends entirely on whether an “offline” or “online” encryption key was used.
    • Online ID Encryption: If the ransomware successfully connected to its command-and-control server during encryption, it generates a unique “online key” specific to your machine. Decryption is not possible without this private key, which only the attackers possess. Paying the ransom is typically the only way to obtain this key, but success is not guaranteed, and it funds criminal activity. The ransom note will indicate an “online ID” was used.
    • Offline ID Encryption: If the ransomware failed to connect to its server (e.g., due to no internet connection at the time of infection), it uses one of a limited set of “offline keys.” Files encrypted with an offline key can sometimes be decrypted if the corresponding offline key has been discovered and released by security researchers. The ransom note will indicate an “offline ID” was used.
  • Essential Tools/Patches:
    • Emsisoft Decryptor for STOP Djvu: This is the primary tool for potentially recovering files encrypted by STOP/Djvu variants. It is developed by security researchers (like Michael Gillespie) and Emsisoft. You can download it from Emsisoft’s official website.
      • How to Use: The decryptor will attempt to identify the encryption key used. If an offline key is matched, it can decrypt your files. If it’s an online key, the tool will indicate that decryption is not possible at this time.
      • Important: You need at least one pair of original (unencrypted) and encrypted files to help the decryptor find the correct key if it’s an offline ID. If you don’t have an original pair, the tool still tries, but its chances might be lower.
    • Shadow Explorer: While STOP/Djvu variants usually delete shadow copies, it’s worth checking with tools like Shadow Explorer to see if any restore points survived. This is a low-probability method but costs nothing to check.
    • Data Recovery Software: Software like PhotoRec or Recuva can sometimes recover deleted original files (before they were encrypted and deleted), but success rates are generally low as encrypted files often overwrite the originals.
    • Data Backups: The most reliable recovery method. Restore your files from clean, uninfected backups after ensuring the ransomware has been completely removed from your system.

4. Other Critical Information

  • Ransom Note: The ransom note is always named _readme.txt. It will contain instructions, the amount of ransom demanded (typically in cryptocurrency like Bitcoin, often $499 or $999 USD), and contact email addresses (e.g., [email protected], [email protected], or the email in the file extension [email protected]).
  • Hosts File Modification: As mentioned, this ransomware modifies the Windows hosts file to block access to security and antivirus websites, preventing users from seeking help or downloading removal tools.
  • System Corruption: In some cases, STOP/Djvu can corrupt the Windows registry or other system files, potentially leading to system instability or boot issues even after file decryption. A full reinstallation of the operating system may be the safest course of action after data recovery.
  • Broader Impact:
    • Widespread Personal Impact: Due to its reliance on common tactics like pirated software, STOP/Djvu affects a large number of individual users, leading to significant personal data loss and distress.
    • Financial Strain: The ransom demands, while typically lower than those from enterprise-targeting ransomware, still represent a significant financial burden for individuals.
    • Ongoing Threat: The continuous release of new variants makes it a persistent threat that security solutions must constantly adapt to.
    • Difficult Decryption: The prevalence of “online ID” encryption makes full data recovery highly challenging without paying the ransom, which is generally discouraged by law enforcement and cybersecurity experts.