*[email protected]*.mails

[Content by Gemini 2.5]

This document provides a comprehensive overview of the ransomware variant identified by the file extension *[email protected]*.mails. This variant is highly indicative of being a derivative or specific campaign of the Dharma ransomware family, known for its pervasive attacks and often manual, post-compromise execution.

Technical Breakdown:

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: The exact file extension used by this ransomware is typically appended in a multi-part format after the original file name, often looking like: .id-[uniqueID].[[email protected]].mails or simply .[[email protected]].mails.
  • Renaming Convention: Files are typically renamed according to the following pattern:
    [original_filename].[id-[8-hex-chars]][email protected]
    For example, document.docx might become [email protected].
    The [uniqueID] part is an identifier specific to the victim or infection, and the email address [email protected] is used by the attackers for communication regarding decryption. The final .mails is the specific extension for this variant.

2. Detection & Outbreak Timeline

  • Approximate Start Date/Period: Variants using the [email protected] contact email, consistent with Dharma ransomware, have been observed in the wild since at least late 2021 through 2023, and possibly into 2024. The Dharma family itself has been active since 2016, with various affiliates and campaigns continuously emerging with new contact emails and slight modifications to the appended extensions. This specific .mails suffix indicates a particular campaign or affiliate that became active during this period.

3. Primary Attack Vectors

  • Propagation Mechanisms: Like other Dharma variants, *[email protected]*.mails primarily leverages common remote access and network vulnerabilities:
    • Remote Desktop Protocol (RDP) Exploitation: This is the most prevalent method. Attackers gain access by:
      • Brute-forcing weak RDP credentials.
      • Purchasing compromised RDP credentials on underground forums.
      • Exploiting vulnerabilities in RDP (though less common for Dharma itself, it can be a gateway).
        Once RDP access is gained, the ransomware is often deployed manually.
    • Phishing Campaigns: Malicious emails containing weaponized attachments (e.g., seemingly legitimate documents with embedded macros, or archives containing executable files) or links to malicious websites that deliver the ransomware payload. These often serve as initial access points, followed by lateral movement.
    • Software Vulnerabilities: Exploitation of unpatched vulnerabilities in public-facing applications (e.g., VPNs, web servers, content management systems) can provide initial access.
    • Supply Chain Attacks: Less frequently, compromise of a legitimate software vendor or service provider can lead to the distribution of malware, including this ransomware, to their customers.
    • Exploitation of SMBv1 (e.g., EternalBlue): While older, unpatched systems are still vulnerable to exploits like EternalBlue (used by WannaCry and NotPetya), Dharma itself doesn’t directly use these. However, systems compromised via such vulnerabilities could then be targeted by Dharma actors through RDP or other internal network access.
    • Compromised Third-Party Software: Exploitation of legitimate software, often through trojanized installers or updates, can also be a vector.

Remediation & Recovery Strategies:

1. Prevention

  • Proactive Measures:
    1. Strong RDP Security:
      • Disable RDP if not strictly necessary.
      • Implement Multi-Factor Authentication (MFA) for all RDP access.
      • Use strong, unique passwords for RDP accounts.
      • Limit RDP access to specific IP addresses via firewall rules or VPN.
      • Monitor RDP logs for unusual activity or failed login attempts.
    2. Regular Backups: Implement a robust 3-2-1 backup strategy (3 copies of data, on 2 different media, with 1 copy off-site/offline). Ensure backups are immutable or regularly tested for restoration.
    3. Patch Management: Keep all operating systems, software, and firmware updated with the latest security patches. Prioritize patches for internet-facing systems and known vulnerabilities.
    4. Endpoint Detection and Response (EDR) / Antivirus (AV): Deploy and maintain reputable EDR or next-generation antivirus solutions on all endpoints and servers. Ensure real-time protection is enabled and signatures are up-to-date.
    5. Network Segmentation: Isolate critical systems and sensitive data from the rest of the network to limit lateral movement in case of a breach.
    6. Principle of Least Privilege: Grant users and systems only the minimum necessary permissions to perform their functions.
    7. Security Awareness Training: Educate employees about phishing, social engineering, and safe browsing practices.

2. Removal

  • Infection Cleanup:
    1. Isolate Infected Systems: Immediately disconnect the infected computer/server from the network (unplug Ethernet, disable Wi-Fi). This prevents further encryption or spread.
    2. Identify and Contain: Determine the extent of the infection. Are other systems affected? If so, isolate them too.
    3. Use Reputable Anti-Malware Tools: Boot the infected system into Safe Mode with Networking (if necessary for updates) or use a bootable anti-malware rescue disk.
      • Perform a full system scan with updated antivirus/anti-malware software (e.g., Malwarebytes, Bitdefender, ESET, Microsoft Defender Offline).
      • Focus on detecting and removing the ransomware executable and any associated malicious files or persistence mechanisms (e.g., registry entries, scheduled tasks, startup folders).
    4. Check for Persistence: Manually inspect common persistence locations (e.g., HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run, HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run, Task Scheduler, Startup folder) for suspicious entries.
    5. Remove Malicious Files: Delete any identified ransomware executables and related dropper files.
    6. Change Credentials: Immediately change all passwords, especially for administrative accounts and RDP accounts, even if you suspect they haven’t been compromised. Consider a password reset for all domain users if a domain controller was affected.
    7. Restore System: After cleaning, the most reliable way to ensure the system is free of lingering threats is to perform a clean reinstallation of the operating system.

3. File Decryption & Recovery

  • Recovery Feasibility: For most recent Dharma variants, including those using the *[email protected]*.mails extension, there is currently no public universal decryptor available. This means that decrypting files without the private key held by the attackers is generally not possible.
    • Do NOT Pay the Ransom: While tempting, paying the ransom does not guarantee file decryption and emboldens attackers. It also provides funds for future attacks.
    • Primary Recovery Method: Backups: The most effective and reliable method for file recovery is to restore data from clean, uninfected backups. This is why robust backup strategies are paramount.
    • Shadow Copies (Volume Shadow Copies Service – VSS): The ransomware often attempts to delete Shadow Copies to prevent self-recovery. However, in some cases, if the deletion failed or partial copies exist, you might be able to recover older versions of files using tools like vssadmin or ShadowExplorer, but this is often not successful for newer variants.
    • Data Recovery Software: In rare cases, if the encryption process was interrupted or certain file types were not fully overwritten, data recovery software might retrieve remnants of original files. However, this is generally unreliable for fully encrypted data.
  • Essential Tools/Patches:
    • Updated Antivirus/Anti-Malware Solutions: For removal and prevention.
    • Microsoft Windows Updates: Crucial for patching RDP vulnerabilities and other system flaws.
    • Firewall: Properly configured to restrict RDP access and block suspicious outbound connections.
    • Backup & Recovery Software: Solutions like Veeam, Acronis, or Windows Server Backup for robust data protection.
    • Network Monitoring Tools: To detect unusual activity and potential lateral movement.
    • Password Managers and MFA solutions: For strengthening credentials.

4. Other Critical Information

  • Additional Precautions:
    • No Decryptor (Generally): Unlike some ransomware families, Dharma variants rarely have public decryptors released by law enforcement or security researchers, largely due to the robust encryption and unique keys.
    • Manual Post-Compromise Activity: Dharma actors often manually navigate the compromised network after gaining initial access. This means they might perform reconnaissance, escalate privileges, and attempt to disable security software before deploying the ransomware. This makes detection crucial before encryption occurs.
    • Ransom Note: The ransomware typically drops a ransom note (e.g., README.txt, info.txt) containing instructions and the contact email address ([email protected]).
  • Broader Impact: The Dharma ransomware family, including this variant, has caused significant disruption to businesses, healthcare organizations, and individuals worldwide. Its reliance on common attack vectors like RDP makes it a persistent threat, emphasizing the need for fundamental cybersecurity hygiene. The continued evolution of contact emails and specific file extensions indicates ongoing activity by different affiliates targeting various sectors.

By understanding the attack methods and implementing the recommended preventative and recovery strategies, individuals and organizations can significantly reduce their risk of falling victim to *[email protected]*.mails and similar ransomware threats.