*[email protected]*.*.wallet

[Content by Gemini 2.5]

The ransomware variant identified by the file extension *[email protected]*.*.wallet is a specific manifestation of the Crysis ransomware family, also widely known as Dharma (and sometimes loosely associated with Phobos due to similar attack vectors and naming conventions). This family has been a persistent threat, evolving its tactics and an ever-changing list of appended extensions and embedded contact emails. The [email protected] string is a direct indicator of its lineage.

This document provides a comprehensive breakdown of this variant and practical strategies for prevention, remediation, and recovery.

Technical Breakdown:

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: The exact file extension used by this particular variant is characterized by a pattern similar to .[unique_ID].[[email protected]].wallet.

  • Renaming Convention: When Crysis/Dharma ransomware encrypts a file, it typically renames it by appending a complex string to the original filename. The general pattern is:
    original_filename.extension.[unique_ID].[attacker_email_address].[custom_extension]

    For this specific variant, the pattern would look like:
    original_filename.extension.id-[alphanumeric_string].[[email protected]].wallet

    Example: A file originally named document.docx might become document.docx.id-A1B2C3D4.[[email protected]].wallet.
    The unique_ID is a hexadecimal string or an alphanumeric sequence generated for each infection. The [[email protected]] part explicitly contains the attacker’s primary contact email, and .wallet is the final, specific extension for this variant.

2. Detection & Outbreak Timeline

  • Approximate Start Date/Period: The Crysis ransomware family itself emerged around mid-2016. Variants using email addresses like [email protected] or similar have been observed since its early days and continued to appear intermittently as the group or its affiliates evolved. While specific peak periods for [email protected] might fluctuate, the underlying Dharma/Crysis framework has remained active and widespread for many years, constantly updating its contact emails and final extensions.

3. Primary Attack Vectors

Crysis/Dharma ransomware, including this variant, primarily leverages the following propagation mechanisms:

  • Remote Desktop Protocol (RDP) Exploitation: This is the most common and historically significant attack vector. Attackers scan the internet for RDP ports (typically 3389) that are exposed and weakly secured. They then perform:
    • Brute-force attacks: Automated tools attempt to guess weak or common RDP credentials (usernames and passwords).
    • Credential stuffing: Using credentials stolen from previous breaches to gain access.
    • Once RDP access is gained, the attackers manually deploy the ransomware.
  • Phishing Campaigns: While less prominent than RDP, spear-phishing emails can be used to deliver the ransomware as an attachment (e.g., seemingly legitimate documents with malicious macros) or via malicious links.
  • Software Vulnerabilities: Exploitation of known vulnerabilities in unpatched software (especially network-facing services or applications) can provide an initial foothold. However, Crysis/Dharma is less known for zero-day exploits and more for exploiting misconfigurations or known N-day vulnerabilities.
  • Supply Chain Attacks: Although not a primary vector for Crysis/Dharma specifically, the compromise of a legitimate software vendor or service could potentially lead to the distribution of this ransomware.
  • Cracked Software / Malvertising: Downloading pirated software, cracks, or engaging with dubious online advertisements can lead to the unwitting installation of malware, including ransomware.

Remediation & Recovery Strategies:

1. Prevention

Proactive measures are the most effective defense against ransomware like Crysis/Dharma.

  • Strong RDP Security:
    • Disable RDP entirely if not strictly necessary.
    • If RDP is required, restrict access to specific IP addresses (e.g., via firewall rules).
    • Use strong, unique passwords for all RDP accounts. Implement a strict password policy.
    • Enable Multi-Factor Authentication (MFA) for RDP access.
    • Consider using a VPN to secure RDP connections, ensuring only authenticated VPN users can access internal RDP.
    • Monitor RDP logs for unusual login attempts.
  • Regular Backups: Implement a robust 3-2-1 backup strategy:
    • 3 copies of your data.
    • On 2 different media types.
    • With 1 copy offsite/offline (air-gapped or immutable cloud storage) to prevent ransomware from encrypting backups.
  • Patch Management: Regularly update operating systems, software, and firmware to patch known vulnerabilities that attackers could exploit.
  • Endpoint Security: Deploy reputable antivirus/anti-malware software with real-time protection, behavior monitoring, and Ransomware Protection modules. Ensure it is kept up-to-date.
  • Network Segmentation: Isolate critical systems and sensitive data from the rest of the network to limit lateral movement in case of a breach.
  • User Training: Educate users about phishing, social engineering, and the dangers of clicking suspicious links or opening unsolicited attachments.
  • Disable SMBv1: Ensure SMBv1 is disabled on all systems, as it is a common target for older exploits and general lateral movement.
  • Least Privilege: Grant users and applications only the minimum necessary permissions to perform their tasks.

2. Removal

If an infection occurs, follow these steps to remove Crysis/Dharma:

  1. Isolate the Infected System: Immediately disconnect the infected computer from the network (unplug Ethernet cable, disable Wi-Fi). This prevents further encryption and lateral movement to other systems.
  2. Identify Infected Systems: Check other computers on the network for similar file extensions or ransom notes.
  3. Boot into Safe Mode: Restart the infected computer and boot into Safe Mode with Networking (if necessary for updates or tool downloads, but preferably without network initially). This loads only essential services, potentially preventing the ransomware from running.
  4. Run a Full System Scan: Use a reputable and up-to-date anti-malware solution (e.g., Windows Defender (updated), Malwarebytes, ESET, Bitdefender). Perform a full, deep scan to detect and remove all components of the ransomware.
  5. Remove Persistence Mechanisms: Manually check common persistence locations (e.g., Startup folders, Registry Run keys, Scheduled Tasks) for suspicious entries created by the ransomware. Delete any identified entries.
  6. Change Credentials: After ensuring the system is clean, change all passwords, especially those for network accounts (RDP, domain accounts, local administrator accounts) that might have been compromised or targeted by the ransomware.

3. File Decryption & Recovery

  • Recovery Feasibility:

    • Direct Decryption (Without Key): For newer variants of Crysis/Dharma (including this *[email protected]*.*.wallet variant), it is generally not possible to decrypt files without the unique decryption key obtained from the attackers. The encryption scheme is robust.
    • Free Decryptors: Emsisoft, in collaboration with law enforcement and cybersecurity researchers, has developed a free decryptor for certain older variants of Dharma/Crysis ransomware. It is always worth trying the Emsisoft Decryptor for Dharma Ransomware as a first step. However, be aware that it may not work for very recent or custom versions like this one, as the keys are specific to each iteration or even each victim.
    • Paying the Ransom: While technically a way to get the decryption key, paying the ransom is strongly discouraged. There is no guarantee you will receive the key or that it will work. Moreover, it emboldens attackers and funds future criminal activities.

  • Recommended Recovery Method:

    • Restore from Backups: The most reliable and recommended method for file recovery is to restore from clean, uninfected backups created before the infection. This underscores the critical importance of a robust backup strategy (as detailed in the Prevention section).
    • Shadow Copies: In some cases, if the ransomware failed to delete Volume Shadow Copies, you might be able to recover previous versions of files. However, most modern ransomware variants, including Dharma, actively attempt to delete these. Tools like ShadowExplorer can help check if they exist.

  • Essential Tools/Patches:

    • For Prevention:
      • Operating System Updates: Windows Updates, Linux apt update/upgrade, macOS updates.
      • Anti-malware/Endpoint Protection Platforms (EPP): Solutions from vendors like Emsisoft, Malwarebytes, Bitdefender, CrowdStrike, SentinelOne, Microsoft Defender for Endpoint.
      • Firewalls: Network and host-based firewalls properly configured.
      • Backup Solutions: Veeam, Acronis, cloud backup services (e.g., Backblaze, Azure Backup, AWS Backup).
      • Password Managers and MFA solutions.
    • For Remediation:
      • Bootable Anti-malware Rescue Disks: For deep scanning (e.g., ESET SysRescue Live, Kaspersky Rescue Disk).
      • Emsisoft Decryptor for Dharma: To attempt decryption for compatible variants.
      • System Restore Points / ShadowExplorer: For potential recovery from shadow copies.

4. Other Critical Information

  • Additional Precautions (Unique Characteristics):

    • Manual Deployment after RDP Breach: Unlike worms that spread automatically, Crysis/Dharma often involves human operators who manually navigate the compromised network after gaining RDP access. This means they might look for high-value targets, delete backups, and ensure maximum impact.
    • Aggressive File Encryption: It targets a wide range of file types and typically encrypts all accessible local and network drives.
    • Persistence: The ransomware often establishes persistence to ensure it runs on system reboot, by creating registry entries, scheduled tasks, or placing itself in startup folders.
    • Ransom Note: The ransom note (often info.txt, FILES ENCRYPTED.txt, RETURN FILES.txt, or an HTA file) provides instructions for contacting the attackers via email (in this case, [email protected]) and usually demands payment in Bitcoin.
    • Evolutionary Nature: The Dharma/Crysis family constantly changes its file extensions and contact emails, making it challenging to track every specific variant. However, the core attack vectors (RDP) and encryption methodologies remain largely consistent.

  • Broader Impact:

    • Significant Data Loss: Without proper backups or a viable decryptor, victims face permanent data loss, leading to severe operational disruption.
    • Financial Costs: Besides potential ransom payments, recovery involves significant costs related to system downtime, IT forensics, data recovery, and implementing stronger security measures.
    • Reputational Damage: For organizations, a ransomware attack can damage reputation, lead to loss of customer trust, and potential regulatory fines if sensitive data is exfiltrated.
    • Resource Drain: Responding to and recovering from a Crysis/Dharma attack consumes substantial IT resources and can divert focus from core business operations.
    • Threat to Critical Infrastructure: Like other ransomware, Crysis/Dharma has the potential to impact critical infrastructure, given its reliance on commonly exposed services like RDP.

By understanding the technical nuances and implementing robust preventative and reactive strategies, individuals and organizations can significantly mitigate the risk and impact of Crysis/Dharma ransomware, including the *[email protected]*.*.wallet variant.