*[email protected]*.com

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As a cybersecurity expert specializing in ransomware, I’ve compiled a detailed resource on the ransomware variant identified by the file extension *[email protected]*.com. This variant is a known iteration of the prolific STOP/Djvu ransomware family, which frequently updates its contact emails and unique file extensions to evade detection and tracking.

Technical Breakdown:

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: The exact file extension used by this variant is typically in the format:
    .id[8-character_hexadecimal_ID][email protected]
    For example, an encrypted file named document.docx would become [email protected].

  • Renaming Convention: The ransomware appends two distinct elements to the original filename:

    1. A unique identifier string (8 hexadecimal characters) prefixed with id. This ID is specific to the infected machine and, more importantly, crucial for identifying the decryption key used.
    2. The contact email address ([email protected]) followed by .com. This serves as both the explicit marker of the encryption and the instruction for contacting the attackers.

    Beyond renaming, the ransomware also drops a ransom note, typically named _readme.txt, in every folder containing encrypted files, and often on the desktop. This note contains instructions for payment and contact information.

2. Detection & Outbreak Timeline

  • Approximate Start Date/Period: Variants using the [email protected] contact email began to emerge and spread around late 2021 to early 2022. The STOP/Djvu ransomware family, to which this variant belongs, has been continuously active since late 2018, releasing new iterations almost daily or weekly with different appended extensions and contact emails. Therefore, while this specific email/extension combo has a more defined period, the underlying ransomware family is persistently evolving.

3. Primary Attack Vectors

*[email protected]*.com (like other STOP/Djvu variants) primarily relies on social engineering and exploiting user vulnerabilities rather than complex network exploits.

  • Propagation Mechanisms:
    • Cracked Software/Pirated Content: This is the most prevalent method. Users download pirated software, key generators, cracked games, or illegal movie/music files from untrusted websites (torrent sites, file-sharing platforms). The ransomware is bundled within these seemingly legitimate installers.
    • Fake Software Updates: Malicious websites or pop-ups might trick users into downloading fake software updates (e.g., for Adobe Flash Player, Java, web browsers) that contain the ransomware payload.
    • Malicious Advertisements (Malvertising): Compromised ad networks or websites display deceptive ads that, when clicked, redirect users to malicious landing pages or initiate drive-by downloads.
    • Phishing Campaigns: Less common for Djvu/STOP variants compared to other ransomware families, but still possible. Malicious email attachments (e.g., seemingly legitimate invoices, shipping notifications, or resumes) containing JavaScript, VBScript, or macro-enabled documents, can drop the ransomware upon execution.
    • Bundled Software: The ransomware might be included as an optional “extra” during the installation of free legitimate software downloaded from less reputable sites.
    • Remote Desktop Protocol (RDP) Exploits (Less Common but Possible): While not its primary vector, weak or exposed RDP connections can be brute-forced, allowing attackers to manually install the ransomware.

Remediation & Recovery Strategies:

1. Prevention

Proactive measures are the most effective defense against *[email protected]*.com and similar ransomware:

  • Regular Data Backups: Implement a robust 3-2-1 backup strategy (3 copies of data, on 2 different media, 1 offsite/cloud). Ensure backups are isolated from the network to prevent encryption.
  • Use Reputable Antivirus/Anti-Malware Software: Keep your security software updated and perform regular scans. Enable real-time protection.
  • Software Updates & Patch Management: Keep your operating system, web browsers, and all installed software updated with the latest security patches to close known vulnerabilities.
  • User Education: Train users to identify phishing emails, suspicious links, and untrusted software sources. Emphasize the dangers of downloading cracked software or visiting dubious websites.
  • Disable Unnecessary Services: Turn off SMBv1 and other legacy protocols if not essential. Disable RDP if not needed, or secure it with strong passwords, 2FA, and network-level authentication.
  • Firewall Configuration: Employ a firewall to block suspicious incoming and outgoing connections.
  • Application Whitelisting: Restrict the execution of unauthorized applications to prevent ransomware from running.

2. Removal

Removing the ransomware is crucial to prevent further encryption or reinfection, but it does not decrypt files.

  • Infection Cleanup (Step-by-step):
    1. Isolate the Infected System: Immediately disconnect the infected computer from the network (unplug Ethernet cable, disable Wi-Fi). This prevents the ransomware from spreading to other devices or encrypting network shares.
    2. Do NOT Pay the Ransom: There’s no guarantee of decryption, and it encourages further attacks.
    3. Boot into Safe Mode: Restart the computer and boot into Safe Mode with Networking. This loads only essential services, often preventing the ransomware process from fully running.
    4. Run a Full System Scan: Use a reputable, updated antivirus/anti-malware program (e.g., Malwarebytes, Emsisoft Anti-Malware, your current AV if it’s updated). Perform a deep, full system scan to detect and remove all ransomware components and associated malware.
    5. Check for Persistence Mechanisms:
      • Examine Startup folders (shell:startup in Run dialog).
      • Check Task Scheduler for suspicious tasks.
      • Inspect Registry Run keys (HKCU\Software\Microsoft\Windows\CurrentVersion\Run, HKLM\Software\Microsoft\Windows\CurrentVersion\Run).
      • Look for suspicious files in %APPDATA%, %TEMP%, C:\ProgramData.
    6. Delete Ransom Note: Once the ransomware executable is removed, delete all _readme.txt files to avoid future confusion.
    7. Change All Passwords: Change passwords for all accounts accessed from the infected machine (email, banking, social media, network shares) after the system is clean and isolated. Assume all credentials on the infected system are compromised.
    8. Monitor System: Continuously monitor the system for any signs of re-infection or unusual activity.

3. File Decryption & Recovery

  • Recovery Feasibility: Decrypting files encrypted by *[email protected]*.com (and other STOP/Djvu variants) is often possible, but not guaranteed, and depends on whether the ransomware used an online key or an offline key for encryption.

    • Online Key: If the victim’s machine was connected to the internet during encryption, the ransomware generates a unique key for that specific infection and transmits it to the attacker’s server. Decryption requires this specific key, which is difficult to obtain without paying the ransom.
    • Offline Key: If the machine was offline or unable to connect to the attacker’s server during encryption, the ransomware uses a pre-generated “offline” key from its internal pool. These offline keys are fewer in number and are often eventually recovered by security researchers.

  • Methods or Tools Available:

    1. Emsisoft Decryptor for STOP/Djvu Ransomware: This is the primary and most successful tool for attempting decryption.
      • Download the official decryptor from Emsisoft’s website: https://www.emsisoft.com/ransomware-decryption-tools/stop-djvu
      • The decryptor attempts to match your ID to known online or offline keys.
      • Important: Provide the decryptor with at least one encrypted file and its original, unencrypted version (if available). This “known pair” significantly helps the decryptor identify the correct key.
      • Decryption success largely depends on whether your files were encrypted with an offline key that has been recovered by researchers. If an online key was used, the decryptor will likely indicate that decryption is not possible with currently available keys.
    2. Data Recovery Software: In some rare cases, professional data recovery software might be able to recover shadow copies or previous versions of files if the ransomware failed to delete them completely. However, Djvu/STOP variants are known to delete Volume Shadow Copies to prevent this.
    3. Cloud Backups/External Drives: The most reliable method of recovery is restoring from clean, verified backups (cloud, external hard drives, NAS) that were not connected to the system during the infection.

  • Essential Tools/Patches:

    • For Prevention: Robust endpoint protection (AV/EDR), firewall, patch management solutions.
    • For Remediation: Emsisoft Decryptor for STOP/Djvu, reputable anti-malware tools (Malwarebytes, SpyHunter, Zemana AntiMalware), a clean bootable USB drive with recovery tools.
    • Patches: Ensure Windows is fully updated, especially for critical vulnerabilities in components like SMB or RDP, though these are less common vectors for this specific variant.

4. Other Critical Information

  • Additional Precautions:

    • Beware of Fake Decryptors: Only use decryptors from reputable cybersecurity companies (like Emsisoft). Scammers often create fake decryptor sites that either install more malware or demand payment without providing a working solution.
    • Preserve Encrypted Files: Do not delete encrypted files, even if decryption isn’t immediately possible. New keys or methods might be discovered in the future. Store them on an isolated drive.
    • Back Up the Ransom Note: Keep a copy of the _readme.txt file (or at least the ID and email from it) as it contains critical information for potential decryption efforts.
    • Isolate Infected Drive: If a drive is heavily infected, consider creating an image of it before attempting extensive remediation, as a forensic copy might be useful later.

  • Broader Impact:

    • Widespread Impact on Individuals: The STOP/Djvu family, including the *[email protected]*.com variant, primarily targets individual users and small businesses due to its reliance on consumer-grade attack vectors (pirated software). This makes it one of the most common ransomware threats encountered by home users.
    • Financial Loss: Victims face potential financial loss from ransom payments (if chosen), data recovery services, or replacement of lost data/systems.
    • Data Loss: For those without backups or unable to decrypt, the permanent loss of personal documents, photos, and critical business data is a significant consequence.
    • Psychological Distress: Dealing with ransomware can be highly stressful, impacting mental well-being due to data loss and the feeling of violation.
    • Continuous Evolution: The rapid iteration of new variants by the STOP/Djvu group makes it a persistent threat that security vendors constantly work to counter. Each new variant requires updated decryption tools, making immediate decryption challenging for newly released versions.