@mail.com*

[Content by Gemini 2.5]

This resource focuses on the ransomware identified by the file extension pattern @mail.com*. It’s important to note that @mail.com* does not typically refer to a distinct, named ransomware family (like Ryuk or LockBit). Instead, it represents a common naming convention used by various ransomware families, most notably STOP/Djvu, Dharma (CrySis), and sometimes Phobos, where the attacker’s contact email address (or a variation containing @mail.com) is appended to the encrypted files, often alongside a unique identifier and a new, random extension. The * in the prompt signifies this variability.

For the purpose of this guide, we will treat @mail.com* as a general descriptor for ransomware that utilizes this specific email-based file extension pattern, drawing insights from the common behaviors and characteristics of the families most likely to employ it.

Technical Breakdown:

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: Files encrypted by ransomware variants exhibiting the @mail.com* pattern will have their original extension replaced or appended with a string that includes an attacker’s email address or a specific identifier followed by a string resembling @mail.com.

  • Renaming Convention: The typical renaming pattern is as follows:
    [original_filename].[original_extension].[unique_id_string].[[email protected]_variant].[new_random_extension]

    Examples:

    The [unique_id_string] is a random alphanumeric string, sometimes prefixed with “id-“, “id[” or similar. The [[email protected]_variant] section will contain the attacker’s email, which often includes @mail.com, @gmail.com, @aol.com, @protonmail.com, or similar public email services. The [new_random_extension] is typically a short, random alphanumeric string or a fixed word chosen by the attacker (e.g., .evil, .decrypt, .btc, .l0ck).

2. Detection & Outbreak Timeline

  • Approximate Start Date/Period: Since @mail.com* is a pattern rather than a single ransomware family, there isn’t a specific start date. However, the ransomware families that commonly employ this pattern (such as STOP/Djvu, Dharma, and Phobos) have been active for several years:

    • Dharma (CrySis): Active since at least 2016, with continuous new variants.
    • STOP/Djvu: Emerged around 2018 and has become one of the most prolific ransomware families, releasing new variants almost daily.
    • Phobos: Identified in late 2018, often considered a variant or successor of Dharma.

    New variants using similar @mail.com based contact emails and extensions continue to emerge regularly, indicating ongoing campaigns.

3. Primary Attack Vectors

Ransomware variants using this naming convention commonly leverage a variety of attack vectors to compromise systems:

  • Malspam/Phishing Campaigns:
    • Email Attachments: Malicious documents (e.g., Word, Excel files with macros), ZIP archives, or executables disguised as legitimate files are sent via email.
    • Malicious Links: Links in emails leading to compromised websites or direct malware downloads.
  • Remote Desktop Protocol (RDP) Exploitation:
    • Weak RDP Credentials: Brute-force attacks or dictionary attacks against systems with weak or default RDP passwords are a primary method, particularly for Dharma and Phobos variants.
    • Exposed RDP Ports: Scanning for publicly exposed RDP ports (3389) and attempting unauthorized access.
  • Software Vulnerabilities:
    • Exploitation of Known Vulnerabilities: Targeting unpatched software, operating systems, or network services (e.g., SMB vulnerabilities like EternalBlue if systems are not updated).
    • Web Application Exploits: Exploiting vulnerabilities in web servers or web applications to gain initial access.
  • Software Cracks/Keygens & Malvertising:
    • Bundling with Pirated Software: Disguising ransomware as legitimate software activators, key generators, or pirated game installers, often downloaded from torrent sites or untrustworthy platforms.
    • Fake Updates: Prompts for fake software updates (e.g., Flash Player, browser updates) that actually download the ransomware payload.
  • Supply Chain Attacks: Less common for these specific families but not impossible, where the ransomware is injected into legitimate software updates or components.

Remediation & Recovery Strategies:

1. Prevention

Proactive measures are crucial to mitigate the risk of @mail.com* ransomware infections:

  • Regular Backups: Implement a robust 3-2-1 backup strategy (3 copies, 2 different media types, 1 offsite/cloud). Ensure backups are isolated from the network to prevent encryption.
  • Patch Management: Keep operating systems, software, and firmware up-to-date with the latest security patches. Prioritize critical vulnerabilities.
  • Strong Password Policies: Enforce strong, unique passwords for all accounts, especially for RDP, VPN, and administrative access. Implement multi-factor authentication (MFA) wherever possible.
  • Network Segmentation: Divide the network into isolated segments to limit the lateral movement of ransomware if an infection occurs.
  • Disable Unused Services: Disable RDP if not needed, and change its default port if it is. Disable SMBv1 and other outdated protocols.
  • Email Security: Deploy email filtering solutions to block malicious attachments and links. Educate users about phishing, spear-phishing, and social engineering tactics.
  • Endpoint Detection and Response (EDR) / Antivirus (AV): Use reputable, up-to-date AV/EDR solutions with real-time protection, behavioral analysis, and exploit prevention.
  • Least Privilege: Grant users and applications only the minimum necessary permissions to perform their tasks.
  • Firewall Configuration: Configure firewalls to block unnecessary incoming connections, especially to RDP and SMB ports from the internet.
  • User Training: Conduct regular cybersecurity awareness training for all employees on identifying phishing attempts, safe browsing, and reporting suspicious activities.

2. Removal

Removing the ransomware typically involves isolating the infected system and using reputable security tools:

  • Isolate the Infected System: Immediately disconnect the compromised computer from the network (unplug Ethernet cable, disable Wi-Fi) to prevent further spread.
  • Identify the Ransomware Process: Use Task Manager, Process Explorer, or other system monitoring tools to identify suspicious processes running from unusual locations (e.g., AppData, Temp folders). Look for high CPU usage or network activity.
  • Terminate Malicious Processes: End the identified ransomware processes. Be cautious, as some ransomware may include self-destruct mechanisms.
  • Boot into Safe Mode: Restart the computer in Safe Mode (with Networking, if necessary for tool downloads) to prevent the ransomware from fully executing on startup.
  • Scan with Antivirus/Anti-Malware: Perform a full system scan using multiple reputable anti-malware tools (e.g., Malwarebytes, HitmanPro, the AV solution already installed). Ensure definitions are up-to-date.
  • Remove Detected Threats: Quarantine and remove all identified malware components.
  • Clean Startup Entries and Registry: Check msconfig (Windows Task Manager > Startup tab), Registry Editor (regedit), and Task Scheduler for persistent ransomware entries and remove them.
  • Delete Shadow Volume Copies: If the ransomware hasn’t already done so, it might delete Shadow Volume Copies (VSS) to prevent easy recovery. To recover from VSS, you’d typically need to do this before infection or if the ransomware failed to delete them. To ensure a clean system, once confident the malware is gone, you might consider wiping any existing VSS to prevent dormant malicious files from being restored.

Warning: Directly interacting with the ransomware (e.g., trying to run the decryptor provided by attackers without expert advice) can cause further damage or re-encryption.

3. File Decryption & Recovery

  • Recovery Feasibility: The possibility of decrypting files without paying the ransom largely depends on the specific ransomware family variant and whether it used an “online” or “offline” encryption key.
    • STOP/Djvu: For STOP/Djvu variants, decryption is often possible if an “offline key” was used (meaning the ransomware couldn’t contact its command-and-control server). Decryptors are periodically updated by cybersecurity researchers (e.g., Emsisoft, Michael Gillespie). If an “online key” was used, decryption without the attacker’s key is extremely difficult, if not impossible, due to strong encryption.
    • Dharma/Phobos: Decryption for Dharma and Phobos variants is generally more challenging without the attacker’s private key. However, sometimes vulnerabilities are found, or law enforcement actions lead to key recovery. Some older variants might have publicly available decryptors.
  • Methods or Tools Available:
    • NoMoreRansom.org: This is the most critical resource. It’s a joint initiative by law enforcement and cybersecurity companies, providing free decryptors for hundreds of ransomware families. Always check this site first.
    • Emsisoft Decryptors: Emsisoft often develops and provides free decryptors for various ransomware families, including many STOP/Djvu variants.
    • Kaspersky, Avast, Trend Micro: Other major cybersecurity vendors also release free decryptors when possible.
    • Data Recovery Specialists: In some highly critical cases, if all else fails, a specialized data recovery firm might be able to help, but this is usually very expensive and not guaranteed.
  • Essential Tools/Patches:
    • NoMoreRansom.org: The primary hub for available decryptors.
    • Emsisoft Decryptors: Specifically for STOP/Djvu variants.
    • Malwarebytes, HitmanPro: For initial scanning and removal.
    • Microsoft Windows Updates: Crucial for patching system vulnerabilities.
    • Strong, Updated Antivirus/EDR Solution: For real-time protection.

4. Other Critical Information

  • Additional Precautions:
    • Email-in-Extension as Identifier: The presence of an email address (especially one from a public service like mail.com) in the file extension is a strong indicator of ransomware and helps narrow down the potential family. Always note the full file extension and the names of any ransom notes (_readme.txt, info.txt, etc.).
    • Ransom Note Analysis: The ransom note itself often contains clues about the ransomware family (e.g., specific language, demands, contact emails, Bitcoin wallet addresses). Do not pay the ransom, but keep the note for forensic analysis.
    • Automated vs. Manual Deployment: While STOP/Djvu is primarily spread via automated means (malware downloaders), Dharma and Phobos often involve manual deployment after an initial RDP breach, allowing attackers to survey the network before encrypting.
  • Broader Impact:
    • Data Loss: The most immediate and significant impact, leading to operational disruption.
    • Financial Costs: Ransom demands (which should not be paid), recovery costs (IT staff, tools, potential third-party specialists), and potential legal/regulatory fines.
    • Reputational Damage: Loss of customer trust, negative media attention, and long-term harm to an organization’s image.
    • Operational Disruption: Downtime of critical systems, inability to access data, and disruption of business processes.
    • Resource Drain: Significant allocation of IT and security resources to respond to and recover from the incident.
    • Potential for Data Exfiltration: While not always the primary goal of these specific variants, some modern ransomware groups combine encryption with data theft, adding a data breach dimension to the incident.