*[email protected]*[email protected]

[Content by Gemini 2.5]

This document provides a comprehensive overview of the ransomware variant identified by the file extension *[email protected]*[email protected]. This particular string pattern is highly indicative of a variant belonging to the Dharma (also known as CrySiS) or Phobos ransomware families, which are known for appending unique email addresses and specific extensions to encrypted files.

Technical Breakdown:

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: The exact file extension used by this ransomware is typically [email protected]@tutanota.com. This full string is appended to the original filename.
  • Renaming Convention: The ransomware follows a pattern characteristic of Dharma/Phobos variants. It encrypts a file and then renames it by appending a unique victim ID, followed by an email address, and then another email address or fixed string as the final extension.

2. Detection & Outbreak Timeline

  • Approximate Start Date/Period: While the specific [email protected]@tutanota.com extension might be part of a more recent campaign, the underlying Dharma/Phobos ransomware families have been active and widely distributed since late 2016/early 2017. These families have seen continuous evolution and new variants appearing regularly, often associated with new contact email addresses. This specific variant likely emerged in 2022 or 2023, given the common rotation of contact emails by ransomware operators.

3. Primary Attack Vectors

This ransomware variant, consistent with its family, primarily relies on opportunistic and targeted exploitation of common vulnerabilities and attack surfaces:

  • Remote Desktop Protocol (RDP) Exploits: This is the most prevalent attack vector. Attackers scan the internet for systems with exposed RDP ports (usually 3389) and then attempt to brute-force weak or default RDP credentials. Once access is gained, they manually deploy the ransomware.
  • Phishing Campaigns: Malicious emails containing weaponized attachments (e.g., seemingly legitimate documents with embedded macros, or archives containing executables) or links to malicious websites that deliver the ransomware payload.
  • Software Vulnerabilities: Exploitation of unpatched vulnerabilities in public-facing applications (e.g., web servers, VPNs, content management systems) can provide an initial foothold.
  • Cracked Software/Malvertising: Users downloading “cracked” software, key generators, or visiting compromised websites may inadvertently download and execute the ransomware.
  • Supply Chain Attacks: Less common for Dharma/Phobos but possible, where legitimate software updates or components are tampered with to include the malware.

Remediation & Recovery Strategies:

1. Prevention

Proactive measures are critical to prevent infection by this and similar ransomware variants:

  • Robust Backup Strategy: Implement and regularly test 3-2-1 backup rule (3 copies of data, 2 different media types, 1 offsite/offline). Ensure backups are isolated from the network to prevent encryption.
  • Secure RDP Access:
    • Disable RDP if not needed.
    • Restrict RDP access to trusted IPs via firewall rules.
    • Use strong, unique passwords and multi-factor authentication (MFA) for all RDP accounts.
    • Change default RDP port (though this is more of an obfuscation than a security measure).
    • Implement account lockout policies for failed login attempts.
  • Patch Management: Keep operating systems (Windows, in particular) and all software up-to-date with the latest security patches. This includes web browsers, office suites, and any server applications.
  • Endpoint Protection: Deploy and maintain robust Anti-Virus (AV) and Endpoint Detection and Response (EDR) solutions. Ensure they are configured to perform real-time scanning and behavioral analysis.
  • Network Segmentation: Isolate critical systems and sensitive data from the rest of the network to limit lateral movement in case of a breach.
  • User Education: Train employees to recognize and report phishing attempts, avoid suspicious links, and be cautious about opening unsolicited attachments.
  • Principle of Least Privilege: Grant users and applications only the minimum necessary permissions to perform their tasks.
  • Disable SMBv1: Ensure SMBv1 is disabled on all systems as it contains known vulnerabilities often exploited by ransomware.

2. Removal

If infected, follow these steps to remove the ransomware:

  1. Isolate Infected Systems: Immediately disconnect the infected computer(s) from the network (unplug Ethernet cable, disable Wi-Fi). This prevents further spread to other systems.
  2. Identify and Quarantine: Use your AV/EDR solution to scan the isolated system. If identified, quarantine or delete the ransomware executable and any related malicious files.
  3. Boot into Safe Mode: Restart the computer in Safe Mode (with Networking, if necessary for updates/downloads) to prevent the ransomware from fully executing its malicious processes.
  4. Full System Scan: Perform a comprehensive scan using reputable anti-malware software (e.g., Malwarebytes, Windows Defender Offline, ESET, Sophos, etc.). Consider a second-opinion scanner.
  5. Remove Persistence Mechanisms: Check common persistence locations like:
    • Registry Run keys (HKCU\Software\Microsoft\Windows\CurrentVersion\Run, HKLM\Software\Microsoft\Windows\CurrentVersion\Run)
    • Startup folders
    • Scheduled Tasks
    • WMI subscriptions
    • Services
    • Review recent user profiles and temporary directories for suspicious executables.
  6. Delete Shadow Volume Copies: The ransomware likely deleted shadow copies to prevent easy recovery. However, if the deletion failed or partial copies exist, attempt to restore previous versions of files or the system. Use vssadmin delete shadows /all /quiet to clean up any remaining malicious shadow copies.
  7. Change Credentials: Immediately change all passwords, especially those for RDP, domain accounts, and local administrator accounts, as they may have been compromised.

3. File Decryption & Recovery

  • Recovery Feasibility: Direct decryption of files encrypted by [email protected]@tutanota.com (as a Dharma/Phobos variant) is generally not possible without the attacker’s private decryption key. These families use strong encryption algorithms (e.g., AES-256 for files and RSA-2048 for the AES key).
    • No More Ransom Project: Always check the No More Ransom website. They host various decryption tools for different ransomware families. While tools exist for some older Dharma/Phobos variants, newer ones like this specific extension often lack a public decryptor.
    • Paying the Ransom: Paying the ransom is strongly discouraged. There is no guarantee you will receive a working decryptor, and it funds criminal activity.
    • Data Recovery: If backups are unavailable, specialized data recovery firms might be able to recover some data, but success is not guaranteed and can be costly.
  • Essential Tools/Patches:
    • Anti-malware software: Reputable AV/EDR solutions (e.g., CrowdStrike, SentinelOne, Microsoft Defender for Endpoint, Sophos, ESET, Bitdefender).
    • Operating System Updates: Keep Windows fully updated to patch known vulnerabilities.
    • RDP Hardening Tools/Practices: Use Group Policy, strong passwords, MFA, and network-level authentication (NLA) for RDP. Consider using an RDP gateway.
    • Backup Solutions: Reliable backup software that supports offsite/offline storage.
    • Firewall: Configure network firewalls to restrict inbound RDP access and block suspicious outbound connections.

4. Other Critical Information

  • Additional Precautions:
    • No Ransom Note on Desktop? While most ransomware drops a ransom note (e.g., info.txt, README.txt, FILES ENCRYPTED.txt), the *[email protected]*[email protected] variant might not always drop a prominent note on the desktop, relying on the file extension itself to indicate the compromise and provide contact information. Always check all directories for ransom notes.
    • System Enumeration: Dharma/Phobos variants typically perform significant system enumeration (e.g., listing network shares, installed software, security products) to tailor their attack or ensure persistence.
    • Lateral Movement: If RDP access was gained to a single workstation, attackers often attempt lateral movement to gain access to domain controllers or file servers for maximum impact.
  • Broader Impact:
    • Significant Data Loss: Without proper backups or a decryptor, organizations and individuals face irreversible data loss.
    • Operational Disruption: Business operations can be severely disrupted, leading to downtime, productivity loss, and financial penalties.
    • Financial Costs: Recovery efforts, forensic investigations, potential reputational damage, and, in some cases, the decision to pay the ransom, incur substantial financial costs.
    • Reputational Damage: Especially for businesses, a ransomware attack can erode customer trust and damage reputation.
    • Legal & Regulatory Consequences: Depending on the data compromised (e.g., PII, healthcare records), there may be legal and regulatory reporting requirements and potential fines (e.g., GDPR, HIPAA).

By understanding the technical aspects and implementing robust prevention and recovery strategies, individuals and organizations can significantly mitigate the risk posed by ransomware variants like *[email protected]*[email protected].