*[email protected]*.meduza

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This document provides a comprehensive overview of the ransomware variant identified by the file extension *[email protected]*.meduza, offering both a technical breakdown and practical recovery strategies for the community. This variant is a known iteration of the MedusaLocker ransomware family.

Technical Breakdown:

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: The exact file extension used by this variant is typically .original_id[[email protected]].meduza. This structure appends a unique ID, the attacker’s contact email, and the specific variant identifier (.meduza) to the encrypted file.
  • Renaming Convention: When a file is encrypted, its original name is modified to incorporate the unique identifier, the specified email address for contact, and the .meduza extension.
    • Example: A file originally named document.docx might be renamed to document.docx.uniqueID[[email protected]].meduza.
    • This pattern clearly indicates the file has been encrypted by this specific ransomware and provides the attackers’ preferred communication channel. A ransom note (e.g., _READ_ME_MEDUSA_.txt or similar) is also typically dropped in affected directories.

2. Detection & Outbreak Timeline

  • Approximate Start Date/Period: The btc2018 string in the contact email suggests that this particular iteration or campaign of MedusaLocker emerged around late 2018 or early 2019. The MedusaLocker family itself was first prominently observed in the wild during late 2018, with various versions and contact emails emerging since then. This specific contact email was active during its initial widespread campaigns.

3. Primary Attack Vectors

The *[email protected]*.meduza variant, as part of the MedusaLocker family, primarily leverages the following propagation mechanisms:

  • Remote Desktop Protocol (RDP) Exploitation: This is one of the most common vectors. Attackers gain unauthorized access to RDP endpoints, often through brute-forcing weak credentials, exploiting unpatched vulnerabilities, or using stolen credentials obtained from infostealer malware or dark web marketplaces. Once inside, they manually deploy the ransomware.
  • Phishing Campaigns & Malicious Emails: Adversaries use sophisticated phishing emails that deliver the ransomware payload either directly as a malicious attachment (e.g., weaponized documents, executables disguised as legitimate files) or via links to compromised websites that host the malware.
  • Software Vulnerabilities: While less common for this specific variant compared to RDP, exploitation of known software vulnerabilities (especially in publicly facing servers, unpatched applications, or outdated operating systems) can also be used as an initial access point.
  • Supply Chain Attacks/Compromised Software: In some cases, ransomware can be distributed through compromised legitimate software updates or third-party tools, though this is a more advanced vector.
  • Exploitation of Weak Network Services: Besides RDP, other weakly secured network services (e.g., SMB, FTP) might be targeted to gain initial access or move laterally within a network.

Remediation & Recovery Strategies:

1. Prevention

Proactive measures are crucial to prevent infection by *[email protected]*.meduza and similar ransomware:

  • Regular & Verified Backups: Implement a robust 3-2-1 backup strategy (3 copies, 2 different media types, 1 offsite/offline). Regularly test backup restoration to ensure data integrity and usability.
  • Strong Password Policies & Multi-Factor Authentication (MFA): Enforce complex, unique passwords for all accounts, especially for RDP, VPNs, and administrative access. Implement MFA wherever possible, particularly for remote access services.
  • Patch Management: Keep all operating systems, software, and firmware updated with the latest security patches. Prioritize patches for known vulnerabilities, especially those affecting RDP and other publicly exposed services.
  • Network Segmentation: Divide your network into isolated segments to limit lateral movement in case of a breach. Restrict RDP access to a specific set of users and implement VPNs or secure gateways for remote access.
  • Endpoint Detection and Response (EDR) / Next-Gen Antivirus: Deploy advanced security solutions that can detect and prevent ransomware execution, including behavioral analysis and machine learning capabilities.
  • Email Security: Implement email filtering solutions to block malicious attachments and phishing attempts. Educate users about identifying and reporting suspicious emails.
  • Disable Unnecessary Services: Turn off or uninstall services and applications that are not essential for business operations (e.g., SMBv1, unnecessary RDP ports).
  • Principle of Least Privilege: Grant users and systems only the minimum necessary permissions to perform their tasks.
  • User Education: Conduct regular security awareness training for all employees on topics like phishing, suspicious attachments, and safe browsing habits.

2. Removal

If an infection by *[email protected]*.meduza is detected, follow these steps for effective removal:

  1. Isolate Infected Systems: Immediately disconnect any infected computers or servers from the network (unplug network cables, disable Wi-Fi). This prevents the ransomware from spreading further.
  2. Identify and Terminate Malicious Processes: Use Task Manager (Windows) or process monitoring tools to identify and stop any suspicious processes. MedusaLocker often runs as a new process or injects itself into legitimate ones.
  3. Remove Ransomware Files: Locate and delete the ransomware executable and any associated files. These are often found in temporary folders (%TEMP%, %APPDATA%), user profiles, or the startup folder. Use a reputable anti-malware scanner to assist with identification and removal.
  4. Scan with Antivirus/Anti-Malware: Perform a full system scan using an up-to-date antivirus or anti-malware program. Consider using multiple scanners (e.g., Malwarebytes, ESET, Sophos) as different tools may detect different components.
  5. Check Startup Entries & Scheduled Tasks: Review msconfig (Windows System Configuration) or Task Scheduler for any new, suspicious entries that might allow the ransomware to persist after a reboot. Remove any such entries.
  6. Review System Logs: Examine event logs (Security, System, Application) for suspicious activities, failed login attempts, or unusual process executions that might indicate how the initial breach occurred.
  7. Change Credentials: After ensuring the system is clean, change all compromised credentials, especially those related to RDP or administrative access.

3. File Decryption & Recovery

  • Recovery Feasibility: As of current knowledge, some versions of MedusaLocker, including those from its earlier campaigns, have seen decryption solutions developed by cybersecurity researchers. The good news is that for some specific variants of MedusaLocker (and potentially this [email protected] version), a free decryptor may be available.
    • No More Ransom Project: The No More Ransom project (nomoreransom.org) is the primary resource for free ransomware decryption tools. Users should visit their site, use the Crypto Sheriff tool to upload a sample encrypted file and the ransom note, and check if a decryptor for MedusaLocker (or this specific variant) is available.
    • Key Management: The effectiveness of a decryptor often depends on the specific variant and how the encryption keys were handled. Some early MedusaLocker variants had flaws that allowed for key recovery.
    • Caution: If no decryptor is available, paying the ransom is generally not recommended. There is no guarantee that the attackers will provide a working decryptor, and it funds future criminal activities.
  • Essential Tools/Patches:
    • No More Ransom Decryptors: Specifically, look for MedusaLocker decryptors.
    • Anti-Malware Software: Up-to-date versions of reputable security suites (e.g., Kaspersky, Bitdefender, ESET, Sophos) for removal.
    • Windows Security Updates: Ensure all Windows updates are applied to patch vulnerabilities.
    • Backup Solutions: Rely on your clean, verified backups for file recovery if decryption is not possible.
    • Vulnerability Scanners: Tools like Nessus, OpenVAS, or Microsoft Baseline Security Analyzer (MBSA) can help identify unpatched systems or misconfigurations.

4. Other Critical Information

  • Additional Precautions:
    • Shadow Copy Deletion: MedusaLocker is known to attempt to delete Volume Shadow Copies (vssadmin delete shadows /all /quiet) to prevent users from recovering files using Windows’ built-in restoration features. This makes reliance on external, offline backups even more critical.
    • Security Software Disabling: The ransomware may try to disable or interfere with antivirus and security software to hinder its detection and removal.
    • Network Share Targeting: Beyond local files, MedusaLocker actively seeks out and encrypts files on accessible network shares, making it particularly disruptive to organizations.
    • Persistence Mechanisms: It often creates new user accounts, modifies startup registry keys, or establishes scheduled tasks to ensure persistence and re-execution.
    • Targeted File Types: It typically targets a wide array of file types crucial for business operations (documents, databases, archives, media files).
  • Broader Impact:
    • Significant Financial Loss: Organizations face not only the potential ransom payment (if chosen) but also costs associated with incident response, system remediation, lost productivity, and potential legal fees.
    • Operational Disruption: Business operations can be severely halted, leading to downtime, missed deadlines, and customer dissatisfaction.
    • Data Loss: If backups are not available or are also compromised, permanent data loss can occur.
    • Reputational Damage: Infections can erode customer trust and damage an organization’s public image, leading to long-term negative consequences.
    • Compliance and Legal Implications: Depending on the industry and data involved (e.g., PII, PHI), a ransomware attack can lead to regulatory fines and legal liabilities under laws like GDPR, HIPAA, etc.

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