*[email protected]*.eth

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This document provides a comprehensive analysis and actionable strategies against the ransomware variant identified by the file extension *[email protected]*.eth. Based on its distinctive naming convention, this variant is unequivocally part of the STOP/Djvu ransomware family, a prolific and continuously evolving threat.

Technical Breakdown:

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: The exact file extension used by this ransomware is appended to encrypted files as [email protected]. For example, a file named document.docx would be renamed to [email protected].
  • Renaming Convention: The ransomware employs a straightforward renaming convention. It takes the original filename, appends the full email contact string, and then appends its unique .eth suffix. This pattern is characteristic of STOP/Djvu variants, where the email address serves as a unique identifier for the specific campaign or version.

2. Detection & Outbreak Timeline

  • Approximate Start Date/Period: While the specific [email protected] variant is a recent addition, the underlying STOP/Djvu ransomware family has been continuously active and evolving since late 2017/early 2018. New variants like this one emerge frequently, often on a weekly or even daily basis. This specific variant likely appeared in recent months, building upon the established infrastructure and code of the broader STOP/Djvu family.

3. Primary Attack Vectors

The *[email protected]*.eth variant, like its Djvu predecessors, primarily relies on social engineering and deceptive practices for propagation.

  • Cracked Software/Pirated Content: This is the most prevalent attack vector. Users often download seemingly legitimate cracked software, key generators, software activators, or pirated media from untrustworthy websites, torrents, or file-sharing platforms. The ransomware is often bundled discreetly within these seemingly innocuous downloads.
  • Malvertising: Malicious advertisements on compromised or rogue websites can redirect users to landing pages that trigger drive-by downloads or trick them into downloading the ransomware.
  • Phishing Campaigns: While less common for Djvu than for some other ransomware families, targeted phishing emails containing malicious attachments (e.g., weaponized documents, archives) or links to compromised sites can also serve as an entry point.
  • Remote Desktop Protocol (RDP) Exploits: In some instances, particularly against businesses, threat actors may gain unauthorized access to weakly secured RDP ports and manually deploy the ransomware.
  • Software Vulnerabilities: Less frequently, unpatched vulnerabilities in common software or operating systems could be exploited, though this is not a primary vector for Djvu.

Remediation & Recovery Strategies:

1. Prevention

Proactive measures are the most effective defense against *[email protected]*.eth and similar threats:

  • Regular Data Backups: Implement a robust 3-2-1 backup strategy (3 copies of data, 2 different media types, 1 offsite/cloud). Ensure backups are stored offline or in immutable cloud storage to prevent them from being encrypted.
  • Educate Users: Train users to identify phishing attempts, be cautious about opening unsolicited attachments, and strongly discourage the download of cracked software or pirated content. This is crucial given Djvu’s primary attack vector.
  • Employ Reputable Antivirus/Endpoint Detection and Response (EDR) Solutions: Keep security software up-to-date with the latest definitions. EDR solutions offer more advanced behavioral analysis capabilities to detect and block new variants.
  • Keep Software Updated: Regularly patch operating systems, web browsers, and all installed applications to close known security vulnerabilities.
  • Strong Password Policies & Multi-Factor Authentication (MFA): Enforce complex passwords and enable MFA for all critical accounts, especially for remote access services like RDP.
  • Network Segmentation: Isolate critical systems and sensitive data from the rest of the network to limit lateral movement in case of an infection.
  • Disable Unnecessary Services: Turn off services like RDP if not explicitly needed, or secure them with strong VPNs and strict access controls if required.

2. Removal

If an infection occurs, swift and decisive action is critical:

  • Isolate the Infected System: Immediately disconnect the infected computer from the network (unplug Ethernet, disable Wi-Fi) to prevent the ransomware from spreading to other devices.
  • Identify and Confirm Infection: Verify the file extensions on encrypted files and locate the ransom note (typically _readme.txt).
  • Do NOT Pay the Ransom: Paying encourages further attacks and offers no guarantee of decryption.
  • Scan and Remove Malware: Boot the infected system into Safe Mode with Networking (if necessary) and perform a full system scan using a reputable and updated antivirus/anti-malware suite. Tools like Malwarebytes, ESET, or similar can often detect and remove the ransomware executable.
  • Check for Persistence Mechanisms: Manually inspect common persistence locations (e.g., Startup folders, Registry Run keys, Scheduled Tasks) for any entries related to the ransomware and remove them.
  • Address Other Dropped Malware: STOP/Djvu frequently drops additional malware, notably information stealers (e.g., Vidar, Azorult, RedLine Stealer). After removing the ransomware, perform thorough scans to identify and remove these secondary infections. Change all passwords for online accounts (email, banking, social media, etc.) immediately, assuming they may have been compromised.

3. File Decryption & Recovery

  • Recovery Feasibility: Decryption of files encrypted by *[email protected]*.eth is sometimes possible, but success largely depends on whether an “online key” or “offline key” was used during encryption.
    • Online Key: Most Djvu infections use unique online keys generated by the attacker’s server. Decryption with an online key is generally not possible without the key from the attackers, as these keys are unique to each victim and campaign.
    • Offline Key: If the victim’s machine was offline or unable to connect to the attacker’s server during encryption, the ransomware uses a hardcoded “offline key.” If security researchers have managed to obtain and publish this specific offline key for the [email protected] variant, then decryption may be possible.
  • Essential Tools/Patches:
    • Emsisoft Decryptor for STOP/Djvu: The Emsisoft team, in collaboration with the “No More Ransom” project, provides a free decryptor for many STOP/Djvu variants. Users should download the latest version and attempt to use it. It will determine if an offline key was used and if a decryptor is available for that specific key. This is the primary tool for attempted decryption.
    • No More Ransom Project: This initiative (nomoreransom.org) is a valuable resource that provides links to free decryptors for numerous ransomware families, including many Djvu variants.
    • Data Recovery Software: In some rare cases, if only file headers were encrypted or if shadow copies (VSS) were not fully deleted, data recovery software might retrieve older, unencrypted versions of files. However, Djvu variants are typically designed to delete VSS.
    • Windows System Restore/Shadow Copies: While Djvu variants often delete Volume Shadow Copies to hinder recovery, it’s always worth checking if any remain.
  • Best Recovery Method: The most reliable method of recovery is to restore data from secure, uninfected backups.

4. Other Critical Information

  • Additional Precautions: The most distinguishing characteristic of the STOP/Djvu family, including the *[email protected]*.eth variant, is its tendency to bundle information-stealing malware with the ransomware payload. This means that even if files are not recovered, personal credentials, cryptocurrency wallet details, browser history, and other sensitive information may have been exfiltrated.
    • Post-Infection Security Audit: After cleaning the system, it is crucial to assume that all passwords for online accounts (especially banking, email, social media, and any services accessed from the infected machine) have been compromised. Change them immediately and enable MFA everywhere possible. Monitor financial accounts for suspicious activity.
  • Broader Impact: The *[email protected]*.eth variant contributes to the broader impact of the STOP/Djvu family, which is one of the most widespread and persistent consumer-level ransomware threats. Its prevalence is due to its effective distribution via cracked software, leading to:
    • Significant Financial Strain: Ransom demands, even if not paid, lead to downtime, recovery costs, and potential data loss.
    • Operational Disruption: Individuals and small businesses lose access to critical files, hindering productivity.
    • Privacy Compromise: The bundling of info-stealers means not only data loss but also potential identity theft and financial fraud, extending the impact beyond just file encryption.
    • Erosion of Trust: Victims may lose trust in digital services and online content.

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