2000usd

[Content by Gemini 2.5]

The ransomware variant identified by the file extension 2000usd is a highly concerning threat, primarily recognized as a new extension used by the prolific STOP/Djvu ransomware family. This family is infamous for its widespread distribution and continuous evolution. Below is a comprehensive breakdown for the community.

Technical Breakdown:

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: The exact file extension used by this variant is .2000usd.
  • Renaming Convention: When a file is encrypted, its name is appended with the .2000usd extension. The typical renaming pattern follows:
    original_filename.original_extension.2000usd
    • Example: A file named document.docx would become document.docx.2000usd. A file named image.jpg would become image.jpg.2000usd.
      The ransomware also typically drops a ransom note. For the .2000usd variant, the ransom note is almost always named _README_2000usd_.txt. This note is usually placed in every folder containing encrypted files and on the desktop.

2. Detection & Outbreak Timeline

  • Approximate Start Date/Period: The STOP/Djvu ransomware family has been active since late 2018/early 2019, consistently releasing new variants with unique file extensions. The .2000usd extension appeared as part of this ongoing evolution, typically emerging in late 2023 to early 2024. This constant generation of new extensions is a tactic to bypass signature-based antivirus detections.

3. Primary Attack Vectors

The 2000usd variant, as part of the STOP/Djvu family, primarily relies on social engineering and deceptive tactics rather than complex exploit chains. Its propagation mechanisms include:

  • Software Piracy/Cracked Software: This is the most prevalent vector. Users often download seemingly free, cracked versions of popular software (e.g., Adobe products, Microsoft Office, video games, system optimizers, key generators) from illicit websites, torrents, or unofficial download portals. The ransomware is bundled within these seemingly legitimate installers.
  • Malicious Downloads: Drive-by downloads from compromised websites or deceptive advertisements can also be a vector, though less common than pirated software.
  • Phishing Campaigns (Less Common for Djvu): While not the primary method, some instances might involve email attachments (e.g., fake invoices, shipping notifications) that, when opened, execute the ransomware payload. However, Djvu is less associated with large-scale email campaigns compared to other ransomware families.
  • Fake Updates: Prompts for fake software updates (e.g., Flash Player, Java) that, when clicked, download the malicious payload.

Remediation & Recovery Strategies:

1. Prevention

Proactive measures are crucial to mitigate the risk of 2000usd infection:

  • Regular Data Backups: Implement a robust 3-2-1 backup strategy (3 copies of data, 2 different media types, 1 offsite/cloud backup). Ensure backups are isolated from the network to prevent encryption.
  • Software Updates & Patching: Keep your operating system (Windows, macOS), web browsers, antivirus software, and all installed applications fully updated. Many attacks exploit known vulnerabilities that have available patches.
  • Reputable Antivirus/Anti-Malware: Install and maintain a high-quality, up-to-date antivirus/anti-malware solution with real-time protection.
  • Ad Blockers & Browser Security: Use reputable ad blockers and browser security extensions to prevent accidental clicks on malicious ads or redirects.
  • User Education & Vigilance:
    • Avoid Pirated Software: Never download or use cracked software, keygens, or pirated content from untrusted sources. This is the single most common infection vector for Djvu ransomware.
    • Email Security: Be extremely cautious with unsolicited emails, especially those with attachments or links. Verify the sender’s identity.
    • Strong Passwords & MFA: Use strong, unique passwords for all accounts and enable Multi-Factor Authentication (MFA) wherever possible, especially for RDP and cloud services.
  • RDP Security: If RDP is exposed to the internet, secure it with strong passwords, MFA, IP whitelisting, and a VPN.

2. Removal

If infected, immediate action is required to prevent further damage:

  1. Isolate the Infected System: Immediately disconnect the infected computer from the internet and any local networks (unplug Ethernet cable, disable Wi-Fi). This prevents the ransomware from spreading and communicating with its command-and-control server.
  2. Identify and Terminate Malicious Processes: Use Task Manager (Ctrl+Shift+Esc) to look for suspicious processes running in the background. While difficult to pinpoint the exact ransomware process, identifying unfamiliar or high-resource-consuming processes can help.
  3. Scan with Reputable Anti-Malware:
    • Boot the computer into Safe Mode with Networking. This often prevents the ransomware from fully loading.
    • Download and run a full system scan with a reputable anti-malware tool (e.g., Malwarebytes, ESET, SpyHunter, or the installed antivirus if it was somehow bypassed). Ensure the definitions are up-to-date.
    • The anti-malware should identify and quarantine/remove the ransomware executable and any associated files.
  4. Remove Persistent Elements:
    • Check Startup Programs (Task Manager -> Startup tab) and Scheduled Tasks (Task Scheduler) for suspicious entries.
    • Clean Temporary Files (%temp%, C:\Windows\Temp).
    • The 2000usd variant (like other Djvu variants) often modifies the Windows Hosts file (C:\Windows\System32\drivers\etc\hosts) to block access to security-related websites. Check this file and remove any suspicious entries.
  5. Change All Passwords: After the system is clean, change all passwords used on the infected machine, especially for online services, email, and network shares.

3. File Decryption & Recovery

  • Recovery Feasibility: The feasibility of decrypting files encrypted by the .2000usd variant depends heavily on whether the ransomware used an “online” key or an “offline” key during encryption.
    • Online Key: If the ransomware successfully communicated with its command-and-control server, it retrieves a unique online key for the victim. Without this specific key, decryption is generally impossible without paying the ransom.
    • Offline Key: If the ransomware failed to connect to its server, it uses a pre-set “offline” encryption key. Many Djvu variants use a limited set of offline keys. If your encryption used an offline key, there is a chance of recovery.
      Tools Available:
    • Emsisoft STOP Djvu Decryptor: This is the most prominent and reliable tool for Djvu variants. It works by checking your encrypted files against a database of known online and offline keys. You will need to submit one encrypted file and the corresponding ransom note to their server to generate your personal ID. If an offline key was used and is known, or if your online key has been collected by researchers, the tool can decrypt your files. However, for newer extensions like .2000usd, the chances are lower unless an offline key was used and identified.
    • Shadow Explorer / Volume Shadow Copies (VSS): Djvu ransomware typically attempts to delete Volume Shadow Copies (VSS) using vssadmin.exe Delete Shadows /All /Quiet. While it often succeeds, sometimes it fails, or only deletes recent ones. You can try using Shadow Explorer to see if older shadow copies exist that might contain unencrypted versions of your files.
    • Data Recovery Software: For severely damaged or partially deleted files, data recovery software (e.g., PhotoRec, Recuva) might be able to recover some previous versions of files, especially if they were not completely overwritten. Success rates vary.
  • Essential Tools/Patches:
    • Emsisoft STOP Djvu Decryptor: Crucial for decryption attempts.
    • Reputable Antivirus/Anti-Malware: For robust protection and removal.
    • Operating System Updates: Windows Updates, specifically, are vital.
    • Backup Solutions: Tools for automated, offsite, and secure backups are the ultimate recovery tool.

4. Other Critical Information

  • Additional Precautions:
    • Hosts File Modification: As mentioned, 2000usd (Djvu) often modifies the hosts file to block access to legitimate security-related websites, making it harder for victims to seek help or download security tools. Always check and reset this file.
    • Ransom Demands: The ransom note typically demands payment in cryptocurrency (Bitcoin), often within a specific timeframe for a discounted price (e.g., $490 for 72 hours, then $980). It is strongly advised not to pay the ransom, as there is no guarantee of decryption, and it fuels the ransomware ecosystem.
    • Information Stealer Component: Many recent Djvu variants are known to also install an information-stealing Trojan (such as Vidar or RedLine Stealer) alongside the ransomware. This means your personal data, passwords, cryptocurrency wallets, and browser information might have been compromised, even if you manage to decrypt your files. It’s critical to assume compromise and change all sensitive passwords after cleaning.
  • Broader Impact:
    • Individual & SMB Focus: STOP/Djvu ransomware, including the 2000usd variant, primarily targets individual users and small to medium-sized businesses (SMBs) through less sophisticated, high-volume distribution methods (like cracked software sites).
    • Constant Evolution: The rapid generation of new file extensions (e.g., ooss, ezaa, kuub, 2000usd) is a hallmark of the Djvu family, making it challenging for antivirus solutions to keep up with signature-based detection.
    • Data Loss & Financial Strain: Despite relatively lower ransom demands compared to enterprise-level ransomware, the cumulative financial impact on victims can be substantial due to data loss, recovery costs, and potential identity theft from information stealer components.
    • Psychological Impact: The loss of irreplaceable personal photos, documents, and memories can cause significant distress to individuals.

By understanding these technical details and implementing the recommended strategies, individuals and organizations can significantly enhance their defenses against the 2000usd ransomware variant and the broader STOP/Djvu threat.