*[email protected]*.adobe

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The ransomware variant identified by the file extension *[email protected]*.adobe appears to be a derivative of a well-known ransomware family, most likely a variant of STOP/Djvu ransomware, given its characteristic file naming convention that incorporates an email address and a specific suffix. While specific details about this exact string as a standalone ransomware name might be limited, its behavior aligns with the broader family it belongs to.

Here’s a detailed breakdown and comprehensive recovery strategy:

Technical Breakdown:

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: The exact file extension used by this ransomware is typically appended to encrypted files in a multi-part format. For *[email protected]*.adobe, it is most commonly observed as:
    .id[victimID_string][email protected]
    Where [victimID_string] is a unique alphanumeric string generated for each victim.

  • Renaming Convention: The ransomware encrypts files and then renames them according to the following pattern:
    [original_filename].[original_extension].id[victimID_string][email protected]
    For example, a file named document.docx might become [email protected].
    Additionally, a ransom note, typically named _readme.txt, is dropped in every folder containing encrypted files. This note contains instructions for payment and the attacker’s contact email.

2. Detection & Outbreak Timeline

  • Approximate Start Date/Period: Variants exhibiting this file extension pattern, particularly those with embedded email addresses, are characteristic of the STOP/Djvu ransomware family. This family has been highly active and continuously evolving since late 2018/early 2019. New variants with slightly altered extensions and contact emails emerge frequently. Therefore, [email protected] likely represents a newer iteration within this persistent family, with its specific emergence likely occurring in late 2023 or early 2024, continuing the trend of new Djvu strains.

3. Primary Attack Vectors

Like its parent family (STOP/Djvu), this variant primarily relies on deceptive and often user-initiated infection methods:

  • Cracked Software/Pirated Content: This is the most prevalent vector. The ransomware is often bundled within installers for pirated software, cracked versions of legitimate applications (e.g., Photoshop, Microsoft Office), key generators (keygens), software activators, and illegal game downloads distributed via torrents, warez sites, and shady download portals. Victims unwittingly execute the ransomware when trying to install the “cracked” software.
  • Malvertising/Fake Updates: Malicious advertisements or pop-ups pretending to be legitimate software updates (e.g., Flash Player, Java, web browser updates) can lead to drive-by downloads or trick users into downloading the ransomware executable.
  • Phishing Campaigns (Less Common for Djvu, but Possible): While not the primary method for Djvu, generic phishing emails with malicious attachments (e.g., seemingly legitimate invoices, shipping notifications, or resumes containing weaponized documents or executables) or links to compromised websites can also deliver the payload.
  • Remote Desktop Protocol (RDP) Exploits (Less Common): While common for other ransomware groups, Djvu variants typically do not primarily use RDP brute-forcing or exploitation. However, if an RDP session is compromised through other means, the ransomware could be manually deployed.
  • Software Vulnerabilities (Rare for Djvu): It’s less common for Djvu variants to exploit sophisticated zero-day or N-day vulnerabilities for initial access. Their strength lies in social engineering and bundling with desirable (but illegal) content.

Remediation & Recovery Strategies:

1. Prevention

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

  • Regular Backups (3-2-1 Rule): Implement a robust backup strategy: 3 copies of your data, on 2 different media types, with 1 copy off-site or air-gapped (disconnected from the network). This is your primary defense against data loss.
  • Endpoint Detection and Response (EDR) / Antivirus (AV): Deploy and maintain reputable EDR or next-generation antivirus solutions with real-time protection, behavioral analysis, and exploit prevention. Keep them updated.
  • Software Updates & Patch Management: Regularly update your operating system, applications, and all software to patch known vulnerabilities that attackers could exploit.
  • User Education: Train users to identify and avoid phishing attempts, suspicious links, and to be wary of downloading software from unofficial or untrusted sources (especially pirated content).
  • Network Segmentation: Isolate critical systems and sensitive data from the rest of the network to limit the lateral spread of ransomware.
  • Strong RDP Security: If RDP is necessary, secure it with strong, unique passwords, multi-factor authentication (MFA), network-level authentication (NLA), and restrict access to trusted IPs only.
  • Disable SMBv1: Legacy SMBv1 is highly vulnerable and should be disabled on all systems.
  • Principle of Least Privilege: Grant users and applications only the minimum necessary permissions to perform their tasks.

2. Removal

Follow these steps to effectively remove the ransomware from an infected system:

  1. Isolate the Infected System: Immediately disconnect the compromised computer from the network (unplug Ethernet cable, disable Wi-Fi). This prevents further encryption of network shares and limits lateral movement to other systems.
  2. Identify and Terminate Malicious Processes: Use Task Manager (Windows) or process monitoring tools to identify suspicious processes. Look for high CPU/disk usage by unknown executables, especially those recently created or located in unusual directories (e.g., %AppData%, %Temp%). Terminate them if confident.
  3. Run a Full System Scan: Boot the infected system into Safe Mode (with Networking, if needed for updates or tool downloads) and perform a comprehensive scan using a reputable anti-malware solution (e.g., Malwarebytes, ESET, Bitdefender, Microsoft Defender). Ensure the definitions are up-to-date. Allow the tool to quarantine or remove all detected threats.
  4. Remove Persistence Mechanisms: Ransomware often creates persistence to relaunch after reboot. Check and remove entries from:
    • Startup Folders: shell:startup
    • Registry Run Keys: HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run and HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run
    • Scheduled Tasks: Use Task Scheduler (taskschd.msc) to look for newly created or suspicious tasks.
  5. Delete Volume Shadow Copies: Most ransomware, including Djvu variants, attempt to delete Volume Shadow Copies (VSCs) to prevent easy recovery. Use vssadmin delete shadows /all /quiet in an elevated Command Prompt to confirm if any remain and delete them to prevent incomplete recovery attempts that might still be linked to the ransomware’s presence.
  6. Review System Logs: Check Windows Event Logs (Security, System, Application) for suspicious activity or errors that might indicate the ransomware’s actions or other compromises.
  7. Change All Passwords: After confirming the system is clean, change all passwords used on the infected machine, especially for online accounts, network shares, and administrator credentials.

3. File Decryption & Recovery

  • Recovery Feasibility:

    • For STOP/Djvu ransomware variants, decryption feasibility heavily depends on whether the ransomware used an “online” or “offline” key for encryption.
      • Online Key: If the ransomware successfully connected to its command-and-control (C2) server during encryption, it typically generates a unique encryption key for the victim, which is then stored on the C2 server. In this scenario, decryption without the attacker’s private key (obtained only by paying the ransom) is generally not possible. Most recent Djvu variants use online keys.
      • Offline Key: If the ransomware failed to connect to its C2 server, it might resort to using a static, pre-defined “offline” key. If security researchers have managed to obtain or brute-force this specific offline key, then decryption might be possible for victims whose files were encrypted with that key.
    • The victimID_string in the file extension (e.g., idBC67DE90) is crucial. Tools like Emsisoft’s decryptor can analyze this ID to determine if an offline key is available for that specific variant.

  • Essential Tools/Patches:

    • Emsisoft Decryptor for STOP/Djvu: This is the primary and most reliable tool for attempting decryption of STOP/Djvu variants. Download it from the official Emsisoft website. It requires access to both an encrypted file and its original, unencrypted version (if possible) for analysis. It will attempt to determine if an offline key exists for your specific id and variant.
    • Data Recovery Software: Even if decryption is not possible, specialized data recovery software (e.g., PhotoRec, Recuva, R-Studio) can sometimes recover older, unencrypted versions of files if they were deleted rather than overwritten, especially from hard drives that were not fully overwritten. Success is limited if VSCs were deleted.
    • System Restore Points / Previous Versions: Check if Windows System Restore points or “Previous Versions” of files exist from before the infection. These can be a lifeline, though ransomware typically deletes them.
    • Cloud Backups/External Drives: The most reliable recovery method is restoring data from clean, uninfected backups stored on cloud services or external drives that were disconnected during the infection.

4. Other Critical Information

  • Additional Precautions:

    • Do NOT Pay the Ransom: Paying the ransom is strongly discouraged. There is no guarantee you will receive a working decryption key, and it fuels the ransomware ecosystem, encouraging further attacks.
    • Ransom Note Analysis: The _readme.txt file (or similar) will provide the exact contact email ([email protected] in this case), payment instructions, and typically a deadline. Do not engage with the attackers directly unless advised by law enforcement or a professional incident response team.
    • Report the Incident: Report the ransomware attack to your local law enforcement agencies (e.g., FBI’s IC3 in the US, National Cyber Security Centre in the UK) and cybersecurity authorities. Provide them with the ransom note, a sample encrypted file, and the file extension. This helps track threat actors and potentially contributes to future decryption efforts.
    • Collect Forensics: If possible, create a forensic image of the infected drive before attempting cleanup. This can be invaluable for incident response teams to understand the attack, identify the entry point, and potentially develop decryption tools.

  • Broader Impact:

    • Significant Data Loss: The primary impact is often the permanent loss of encrypted data if no viable decryption key or clean backups are available.
    • Operational Disruption: Ransomware attacks can halt business operations, leading to significant downtime and loss of productivity.
    • Financial Costs: Beyond the potential ransom payment, organizations face substantial costs for incident response, system remediation, data recovery, and potential legal fees or regulatory fines if sensitive data was compromised.
    • Reputational Damage: For businesses, a ransomware attack can severely damage customer trust and brand reputation.
    • Supply Chain Risk: If a business in a supply chain is hit, it can disrupt operations for interconnected partners.
    • Psychological Toll: For individuals and small businesses, the stress and frustration of losing irreplaceable files can be immense.

By understanding the nature of this ransomware variant and implementing robust cybersecurity practices, individuals and organizations can significantly mitigate their risk and improve their chances of recovery.