*[email protected]*.adobe

[Content by Gemini 2.5]

This detailed resource is designed to provide individuals and organizations with critical information about the ransomware variant identified by the file extension *[email protected]*.adobe. This variant belongs to the prolific and continuously evolving STOP/Djvu ransomware family, which has plagued users for several years.

Technical Breakdown:

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: The exact file extension used by this variant is typically .[random_characters][email protected]. The [random_characters] part is a unique 4-character ID (e.g., .[abcd][email protected]). This specific combination ([email protected]) serves as the unique identifier for this particular variant within the broader STOP/Djvu family.

  • Renaming Convention: When a file is encrypted, the ransomware appends this complex extension to the original filename. The typical renaming pattern follows this structure:
    original_filename.original_extension.[4_random_characters][email protected]

    Example:

2. Detection & Outbreak Timeline

  • Approximate Start Date/Period: The STOP/Djvu ransomware family has been active since late 2017/early 2018. New variants, often distinguished by their unique appended extensions (like [email protected]), are released by the threat actors on a near-daily basis. This specific [email protected] variant would be a more recent iteration within this ongoing campaign, emerging at a point in the family’s long operational history (e.g., mid-to-late 2023 or early 2024, given its typical release cadence). It’s part of a continuous wave rather than a single, distinct outbreak event.

3. Primary Attack Vectors

*[email protected]*.adobe and other STOP/Djvu variants primarily rely on social engineering and deceptive tactics to gain initial access and execute on systems. They typically do not exploit network vulnerabilities like EternalBlue or SMBv1 directly for propagation within a network, but rather focus on individual system compromise.

  • Propagation Mechanisms:
    • Cracked Software & Illicit Downloads: This is by far the most common infection vector. Users download “cracked” versions of popular software (games, productivity suites, graphic design tools, operating systems, etc.) from torrent sites, warez forums, or illicit download portals. The ransomware is bundled within these seemingly legitimate installers.
    • Fake Software Updates: Malicious websites may mimic legitimate software update pages (e.g., for Adobe Flash Player, Java, web browsers) and trick users into downloading and executing a malicious updater.
    • Malvertising & Redirects: Clicking on deceptive advertisements or being redirected to malicious websites can lead to an automatic download or prompt to download a seemingly harmless file that contains the ransomware.
    • Infected Email Attachments (Less Common for Djvu): While less prevalent than for other ransomware families, email spam campaigns containing malicious attachments (e.g., seemingly legitimate invoices, shipping notifications) can also be used. However, STOP/Djvu prefers the “drive-by-download” or “user-initiated download” model via pirated software.
    • Exploitation of RDP (Rare): While possible for any ransomware, direct brute-forcing of RDP or exploitation of RDP vulnerabilities is not a primary or common propagation method for typical STOP/Djvu infections, which target a broader, less technically sophisticated user base.

Remediation & Recovery Strategies:

1. Prevention

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

  • Regular Backups: Implement a robust 3-2-1 backup strategy: at least 3 copies of your data, stored on 2 different media types, with 1 copy off-site or air-gapped (disconnected from the network). Test your backups regularly.
  • Reputable Anti-Malware Software: Install and maintain a high-quality antivirus/anti-malware solution with real-time protection enabled. Ensure it is updated daily.
  • Operating System & Software Updates: Keep your operating system, web browsers, and all installed software (especially third-party applications) fully patched and up-to-date. This closes security vulnerabilities that might otherwise be exploited.
  • User Education: Educate users about the dangers of downloading cracked software, clicking suspicious links, or opening attachments from unknown senders. Emphasize the importance of verifying software sources.
  • Network Segmentation: For organizations, segmenting your network can limit the lateral movement of ransomware if an infection occurs in one part of the network.
  • Disable/Restrict RDP: If RDP is necessary, ensure it’s secured with strong, complex passwords, multi-factor authentication (MFA), and restricted to specific IP addresses.
  • Firewall Configuration: Employ a firewall to block unsolicited incoming connections and restrict outbound connections to known malicious IP addresses.

2. Removal

If your system is infected, follow these steps to remove *[email protected]*.adobe. Note: Removing the ransomware does not decrypt your files.

  1. Isolate the Infected System: Immediately disconnect the infected computer from the internet and any local networks (unplug Ethernet cable, disable Wi-Fi). This prevents the ransomware from spreading or further communicating with command-and-control servers.
  2. Identify and Stop Malicious Processes:
    • Open Task Manager (Ctrl+Shift+Esc or Ctrl+Alt+Del -> Task Manager).
    • Look for suspicious processes with high CPU or disk usage, especially those with unusual names or located in temporary folders. Right-click and “End task.”
    • Be cautious, as critical system processes can look similar. If unsure, proceed to the next step.
  3. Scan with Reputable Anti-Malware:
    • Boot the infected system into Safe Mode with Networking (if possible) or use a bootable anti-malware rescue disk (e.g., from Emsisoft, Kaspersky, Bitdefender).
    • Perform a full system scan with your updated anti-malware software. Allow it to quarantine or remove all detected threats.
    • Consider using a secondary scanner for an additional layer of detection (e.g., Malwarebytes, HitmanPro).
  4. Remove Persistence Mechanisms:
    • Check common ransomware persistence locations:
      • Registry: HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run, HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run
      • Startup Folders: C:\Users\[Username]\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Startup and C:\ProgramData\Microsoft\Windows\Start Menu\Programs\Startup
      • Scheduled Tasks: Open Task Scheduler (search in Start Menu) and look for suspicious tasks set to run at login or periodically.
    • Delete any entries related to the ransomware.
  5. Delete Ransom Note and Malicious Files: Locate and delete the ransom note (_readme.txt usually found on the desktop and in encrypted folders) and any residual ransomware files, often found in %AppData%, %Temp%, or %Local% directories.
  6. Change All Passwords: Change passwords for all accounts accessed from the infected machine (email, banking, social media, network shares) after you are certain the system is clean, or from a different, clean device. This is crucial as STOP/Djvu often drops information stealers alongside the ransomware.

3. File Decryption & Recovery

  • Recovery Feasibility:

    • Online ID (Highly Probable): For *[email protected]*.adobe, it is highly probable that your unique victim ID (the 4 random characters in the extension) is an “online ID.” This means a unique encryption key was generated on the attacker’s server specifically for your machine. Decryption without the attacker’s private key is generally impossible for online IDs.
    • Offline ID (Rare): In rare cases, if the ransomware failed to connect to its command-and-control server during encryption, it might use an “offline ID” (often identifiable by a specific suffix like t1). For these “offline IDs,” it might be possible to decrypt files if security researchers manage to crack the master offline key or find a flaw. However, new variants almost exclusively use online IDs.

  • Methods or Tools Available:

    • Emsisoft Decryptor for STOP/Djvu Ransomware: This is the most reliable and widely recommended tool. It is developed by security researchers, including Michael Gillespie, who has extensively studied STOP/Djvu.
      • How it works: You download the decrypter, select a pair of encrypted and original (unencrypted) files (if available), or let it scan for known patterns. The tool will attempt to identify your victim ID and check if a decryption key is known for that ID (primarily for offline IDs or previously cracked online IDs).
      • Important Note: If your ID is an “online ID,” the decrypter will likely inform you that your files are “not decryptable at this time.” This means the key is not public, and paying the ransom is the only way the attackers offer decryption (which is never guaranteed and not recommended).
    • Data Recovery Software: Tools like PhotoRec, Recuva, or DiskDrill might recover some original, unencrypted files if they were recently deleted or if the ransomware failed to completely overwrite them or delete Shadow Volume Copies. However, STOP/Djvu typically attempts to delete Shadow Volume Copies, limiting this method’s effectiveness.
    • System Restore: If you have system restore points created before the infection, you might be able to revert your system state. However, the ransomware often attempts to delete these.

  • Essential Tools/Patches:

    • Anti-Malware Suite: A comprehensive, up-to-date anti-malware suite (e.g., Bitdefender, Kaspersky, ESET, Sophos, Malwarebytes) for both prevention and removal.
    • Emsisoft Decryptor for STOP/Djvu: The primary tool for attempting decryption.
    • Windows Security Updates: Ensure all critical Windows updates are installed.
    • Software Updates: Keep all third-party applications (browsers, plugins, PDF readers, office suites) updated to their latest versions.

4. Other Critical Information

  • Additional Precautions (Unique Characteristics):

    • Ransom Note: The ransomware typically drops a text file named _readme.txt (or similar) on the desktop and in every folder containing encrypted files. This note contains instructions for contacting the attackers (using the [email protected] email address) and the ransom demand (usually in Bitcoin).
    • Information Stealer Payload: A critical and often overlooked aspect of STOP/Djvu variants, including *[email protected]*.adobe, is that they frequently drop additional malware alongside the ransomware. This can include information stealers like RedLine Stealer, Vidar, or Azorult. These stealers are designed to pilfer passwords, cryptocurrency wallets, browser data, and other sensitive information from the infected system before encryption takes place. This makes complete system wipe and password changes across all accounts an absolute necessity post-infection.
    • Persistence: The ransomware often establishes persistence by creating new registry entries in Run keys or creating scheduled tasks to ensure it restarts with the system.
    • Shadow Copy Deletion: It attempts to delete all Shadow Volume Copies on the system using vssadmin.exe Delete Shadows /All /Quiet to prevent easy recovery of previous versions of files.

  • Broader Impact:

    • Widespread Impact: STOP/Djvu is one of the most prevalent ransomware families, particularly affecting individual users and small to medium-sized businesses (SMBs) who may be more susceptible to social engineering tactics and less likely to have robust backup solutions.
    • Continuous Evolution: The rapid release of new variants (distinguished by different appended extensions and contact emails) makes it a persistent threat, constantly challenging security researchers and users.
    • Financial and Data Loss: Beyond the immediate financial demand, the most significant impact is often the permanent loss of encrypted data for which no decryption key is publicly available. The addition of information stealers further compounds the damage by compromising sensitive personal and financial data.
    • Trust and Reputation: For businesses, an infection can lead to a loss of customer trust and reputational damage, especially if sensitive data is exfiltrated by accompanying info-stealers.

By understanding the technical nuances and implementing robust prevention and recovery strategies, individuals and organizations can significantly reduce their risk and mitigate the impact of the *[email protected]*.adobe ransomware variant.