*[email protected]**id-**.void

[Content by Gemini 2.5]

As a cybersecurity expert specializing in ransomware, I’ve compiled a detailed resource regarding the ransomware variant identified by the file extension *[email protected]**id-**.void. This variant is part of the prolific STOP/Djvu ransomware family, which has seen continuous development and new variants emerging regularly.

Technical Breakdown:

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: The exact file extension used by this variant is [email protected][victimID].void.
  • Renaming Convention: This ransomware follows a distinct pattern characteristic of the STOP/Djvu family. For an original file named document.docx, it would be renamed to something like [email protected], where:
    • document.docx is the original filename.
    • [email protected] is the attacker’s primary contact email, appended to the filename.
    • id-A1B2C3D4 is a unique victim ID generated for the infected system.
    • .void is the final, static ransomware extension.

2. Detection & Outbreak Timeline

  • Approximate Start Date/Period: Variants using the [email protected] contact first began to be observed in late 2023 and early 2024. The STOP/Djvu family itself has been active since late 2018, constantly releasing new iterations with updated extensions and contact details.

3. Primary Attack Vectors

  • Propagation Mechanisms: The *[email protected]**id-**.void variant, like most STOP/Djvu ransomware, primarily relies on social engineering and deceptive downloads rather than exploiting network vulnerabilities (like EternalBlue or RDP exploits, though compromised RDP could still be a pathway). The most common propagation mechanisms include:
    • Cracked Software/Pirated Content: Distribution via websites offering pirated software, cracked versions of legitimate programs, key generators (keygens), and software activators (e.g., KMSPico). Users downloading and executing these seemingly legitimate tools unknowingly install the ransomware.
    • Malicious Downloads: Drive-by downloads from compromised websites or deceptive advertisements that trick users into downloading malicious executables.
    • Phishing Campaigns: Less common for Djvu, but not unheard of. Malicious attachments (e.g., infected Word documents with macros, ZIP archives containing executables) delivered via spam emails designed to look like legitimate correspondence.
    • Fake Updates: Prompts for fake software updates (e.g., Flash Player, browser updates) that, when clicked, download and execute the ransomware.
    • Bundling: The ransomware executable might be bundled with other seemingly legitimate freeware or shareware downloaded from untrustworthy sources.

Remediation & Recovery Strategies:

1. Prevention

  • Proactive Measures:
    • Avoid Pirated Software: Never download or use cracked software, keygens, or software activators from untrusted sources. This is the single most common infection vector for STOP/Djvu.
    • Robust Antivirus/EDR: Implement and maintain a reputable antivirus or Endpoint Detection and Response (EDR) solution with real-time protection enabled. Ensure it is updated regularly.
    • Regular Backups: Implement a comprehensive backup strategy following the 3-2-1 rule (3 copies of data, 2 different media types, 1 copy offsite/offline). Regularly test your backups to ensure recoverability.
    • Software Updates: Keep your operating system, applications, and all software (especially browsers and plugins) fully patched and updated to fix known vulnerabilities.
    • Email Security Awareness: Be highly suspicious of unsolicited emails, especially those with attachments or links. Verify the sender’s identity before clicking anything.
    • Firewall Configuration: Use a firewall to block suspicious outbound connections and restrict unnecessary inbound access.
    • Disable PowerShell for Users: If not required for legitimate operations, consider disabling PowerShell for standard users or implementing strict execution policies to prevent script-based attacks.
    • Block Common Ransomware Domains: Some organizations block known C2 (Command and Control) domains associated with ransomware, though these change frequently.

2. Removal

  • Infection Cleanup:
    1. Isolate the System: Immediately disconnect the infected computer from the network (unplug Ethernet cable, disable Wi-Fi). This prevents the ransomware from spreading to other devices on the network.
    2. Identify and Terminate Processes: Use Task Manager (Windows) or process explorer tools to identify and terminate any suspicious processes. While difficult to pinpoint the exact ransomware process, looking for newly started, high-resource-consuming processes can help.
    3. Scan with Antivirus/Anti-Malware: Boot the system into Safe Mode with Networking (if possible) or use a bootable antivirus rescue disk. Perform a full system scan with your updated antivirus/anti-malware software (e.g., Malwarebytes, Emsisoft, your existing AV solution). Allow the software to quarantine or remove all detected threats.
    4. Check Startup Items and Scheduled Tasks: Review and remove any suspicious entries in startup folders, registry keys (e.g., HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run), and Task Scheduler that could re-launch the ransomware.
    5. Clean Host File: This Djvu variant may modify the hosts file (C:\Windows\System32\drivers\etc\hosts) to block access to security-related websites. Open the hosts file with Notepad (as Administrator) and remove any suspicious entries that redirect security sites (e.g., malwarebytes.com, emsisoft.com, microsoft.com) to 127.0.0.1 or 0.0.0.0.
    6. Remove Residual Files: Manually delete any suspicious files found in temporary directories (%TEMP%), %AppData%, %LocalAppData%, and C:\ProgramData.
    7. Change Passwords: Once the system is clean (or from a clean system), change all passwords that might have been compromised, especially for online accounts, email, and network resources. This is crucial as Djvu often drops an information stealer before encryption.
    8. Re-evaluate Security: Perform a thorough security audit to understand how the infection occurred and implement additional preventative measures.

3. File Decryption & Recovery

  • Recovery Feasibility: Decrypting files encrypted by *[email protected]**id-**.void (and other STOP/Djvu variants) is highly challenging due to its use of strong encryption algorithms.
    • Online Keys (Most Common): If the ransomware successfully connected to its command and control (C2) server during encryption, it uses a unique “online key” for each victim. In this scenario, decryption without the attacker’s master key is virtually impossible. Paying the ransom is strongly discouraged as there’s no guarantee of receiving a working decryptor, and it funds criminal activity.
    • Offline Keys (Less Common): In rare cases, if the ransomware fails to connect to its C2 server, it might resort to using a static “offline key.” If your files were encrypted with an offline key and security researchers have managed to recover that specific key, decryption might be possible.
    • Emsisoft Decryptor for STOP/Djvu: Emsisoft provides a free decryptor tool for STOP/Djvu ransomware. This tool attempts to decrypt files using known offline keys or, if provided with a pair of original and encrypted files, tries to discover the key. It’s the primary tool to attempt decryption, but its success hinges on whether an offline key was used and is known.
    • Backup Restoration: This remains the most reliable and recommended method for recovering your files. If you have clean, uninfected backups, restore your data from them.
    • Shadow Volume Copies: While Djvu variants often attempt to delete Shadow Volume Copies to prevent recovery (vssadmin delete shadows /all /quiet), it’s still worth checking. Use tools like ShadowExplorer to see if any previous versions of your files are available.
    • Data Recovery Software: Sometimes, data recovery software can retrieve previous, unencrypted versions of files, especially if they were overwritten rather than securely deleted. This is a long shot but can be attempted as a last resort.
  • Essential Tools/Patches:
    • Emsisoft Decryptor for STOP/Djvu: The primary tool for attempting decryption. Download only from official sources (Emsisoft website).
    • Reputable Antivirus/Anti-Malware Software: (e.g., Malwarebytes, Bitdefender, ESET, Avast, AVG, Windows Defender) for removal.
    • Backup and Recovery Solutions: Cloud backup services (OneDrive, Google Drive, Dropbox, iCloud) or local backup software (Veeam, Acronis, Macrium Reflect).
    • ShadowExplorer: To check for and recover Shadow Volume Copies.
    • OS and Application Patch Management Tools: To ensure systems are up-to-date.

4. Other Critical Information

  • Additional Precautions:
    • Information Stealer Presence: A critical characteristic of the STOP/Djvu family is that it frequently drops an information-stealing malware (e.g., Vidar, RedLine, Azorult) before encrypting files. This means that even if you can recover your files, your sensitive information (passwords, cryptocurrency wallets, browser data, system info) might have already been exfiltrated. Assume your credentials are compromised and change all critical passwords from a clean system.
    • Ransom Note: The ransomware typically drops a ransom note named _readme.txt in every folder containing encrypted files, and often on the desktop. This note contains instructions for contacting the attackers (usually via the [email protected] email address) and details on how to pay the ransom.
    • Host File Modification: As mentioned, it frequently modifies the hosts file to block access to security vendor websites, making it harder for victims to seek help or download removal tools.
  • Broader Impact: The STOP/Djvu family, including the *[email protected]**id-**.void variant, primarily targets individual users and small to medium-sized businesses (SMBs). Its wide distribution via cracked software leads to a high volume of infections. The broader impact includes:
    • Significant Financial Losses: Due to ransom demands, recovery costs, and productivity loss.
    • Irrecoverable Data Loss: If backups are not available or are also compromised, or if decryption is not possible.
    • Privacy Compromise: Due to the associated information stealer malware.
    • Reputational Damage: Especially for businesses that suffer data breaches or service disruptions.
    • Resource Drain: For IT departments and cybersecurity professionals dealing with cleanup and recovery efforts.

By understanding the technical nuances and implementing robust prevention and recovery strategies, individuals and organizations can significantly reduce their risk and impact from *[email protected]**id-**.void and similar ransomware threats.