2ourt0

[Content by Gemini 2.5]

This document provides a comprehensive overview of the ransomware variant identified by the file extension 2ourt0, including its technical characteristics and recommended recovery strategies.

Technical Breakdown:

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: The ransomware variant uses the file extension .2ourt0 to mark encrypted files.
  • Renaming Convention: When a file is encrypted by this ransomware, its original name is appended with the .2ourt0 extension.
    • Example: A file originally named document.docx would be renamed to document.docx.2ourt0. An image file photo.jpg would become photo.jpg.2ourt0.
    • The ransomware also typically drops a ransom note named _readme.txt in every folder containing encrypted files, and sometimes on the desktop. This note contains instructions for the victim on how to pay the ransom to decrypt their files.

2. Detection & Outbreak Timeline

  • Approximate Start Date/Period: The .2ourt0 variant is part of the extensive Stop/Djvu ransomware family. Stop/Djvu has been active since at least 2018, with new variants constantly emerging, often daily. The .2ourt0 specific variant likely appeared as part of an ongoing campaign, fitting into the continuous evolution of the Djvu strain. Its precise initial detection date is difficult to pinpoint due to the rapid proliferation of new extensions within this family, but it would fall within the broader, persistent Stop/Djvu activity.

3. Primary Attack Vectors

The 2ourt0 (Stop/Djvu) ransomware primarily relies on social engineering and deceptive tactics to gain initial access:

  • Cracked Software/Freeware Downloads: This is one of the most common vectors. Victims often download seemingly legitimate cracked software, pirated games, key generators, or freeware from unofficial websites, torrents, or file-sharing platforms. The ransomware is often bundled within these downloads, disguised as part of the installer or application.
  • Phishing Campaigns: Malicious attachments (e.g., infected Office documents, ZIP archives) or links embedded in phishing emails can be used to deliver the ransomware payload. These emails often impersonate legitimate entities (e.g., shipping companies, financial institutions, government agencies).
  • Malvertising/Compromised Websites: Visiting compromised websites or clicking on malicious advertisements can trigger drive-by downloads or redirect users to pages designed to exploit browser vulnerabilities or trick them into downloading the malware.
  • Remote Desktop Protocol (RDP) Exploits: While less common for Djvu specifically compared to some other ransomware families, weak or exposed RDP credentials can still be exploited to gain unauthorized access to a system, allowing attackers to manually deploy the ransomware.
  • Software Vulnerabilities: Although less frequently associated with Djvu, unpatched vulnerabilities in operating systems or applications (e.g., web browsers, media players, office suites) can be exploited to facilitate infection.

Remediation & Recovery Strategies:

1. Prevention

Proactive measures are crucial to prevent a 2ourt0 infection:

  • Regular Data Backups: Implement a robust 3-2-1 backup strategy (3 copies of data, 2 different media types, 1 copy off-site/offline). Ensure backups are immutable or stored offline/on air-gapped systems to prevent them from being encrypted.
  • Software & OS Updates: Keep your operating system, applications, and antivirus software fully patched and up-to-date. This closes security vulnerabilities that ransomware might exploit.
  • Strong Password Practices & MFA: Use strong, unique passwords for all accounts and enable Multi-Factor Authentication (MFA) wherever possible, especially for RDP and critical services.
  • Antivirus/Endpoint Detection & Response (EDR): Deploy reputable antivirus or EDR solutions with real-time protection and behavioral analysis capabilities. Keep their definitions updated.
  • Email Security: Implement email filters to block malicious attachments and phishing attempts. Educate users about identifying and reporting suspicious emails.
  • Network Segmentation: Segment networks to limit the lateral movement of ransomware in case of a breach.
  • User Education: Train employees on cybersecurity best practices, including identifying phishing attempts, safe browsing habits, and avoiding suspicious downloads.
  • Disable Unnecessary Services: Disable RDP if not needed, and if needed, secure it with strong passwords, MFA, and VPN access.
  • Principle of Least Privilege: Grant users and applications only the minimum necessary permissions to perform their tasks.

2. Removal

If infected with 2ourt0, follow these steps for cleanup:

  1. 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.
  2. Identify the Threat: Do not delete files immediately. The ransomware executable might still be present.
  3. Run a Full System Scan: Boot the infected system into Safe Mode with Networking (if necessary to update definitions) and perform a full scan using a reputable and up-to-date antivirus/anti-malware program (e.g., Windows Defender, Malwarebytes, ESET, Bitdefender, Sophos). This will detect and remove the ransomware executable and any associated malware.
  4. Check for Persistence: After removal, manually check common persistence locations (e.g., Startup folders, Registry Run keys, Scheduled Tasks) for any remnants. Tools like Autoruns from Sysinternals can assist with this.
  5. Change Credentials: Change all passwords for accounts accessed from or stored on the compromised system, especially those for network shares, cloud services, and email. Assume they might have been compromised.

3. File Decryption & Recovery

  • Recovery Feasibility:
    • Online vs. Offline Keys: Like other Stop/Djvu variants, 2ourt0 uses a combination of online and offline encryption keys. If the infected system has an active internet connection during encryption, it uses an “online key” unique to the victim, making decryption without the attacker’s master key extremely difficult. If there’s no internet connection, it uses an “offline key” which is hardcoded into the ransomware and is the same for many victims, potentially allowing for recovery if this key is known or cracked.
    • Emsisoft Decryptor: Emsisoft, in cooperation with cybersecurity researchers, has developed a decryptor for many Stop/Djvu variants. You can download and attempt to use the Emsisoft Decryptor for STOP Djvu Ransomware. Note: This decryptor primarily works if your files were encrypted with an offline key or if the specific online key used on your system has been recovered by researchers. It’s often unable to decrypt files encrypted with unique online keys.
    • No Guarantee of Decryption: For many victims, especially those encrypted with online keys, there may be no public decryptor available, and paying the ransom is not recommended as it funds criminal activities and does not guarantee file recovery.
  • Primary Recovery Method: Backups: The most reliable and recommended method for file recovery is to restore your data from clean, uninfected backups created before the infection.
  • Shadow Volume Copies: 2ourt0 ransomware often attempts to delete Shadow Volume Copies (VSS) using commands like vssadmin delete shadows /all /quiet. If the deletion was unsuccessful for any reason, you might be able to recover some files using tools like ShadowExplorer, but this is often a long shot.
  • Essential Tools/Patches:
    • Reputable Antivirus/Anti-malware: For detection and removal.
    • Backup Solutions: Robust backup software and storage.
    • Operating System Updates: Critical for preventing exploitation of known vulnerabilities.
    • Emsisoft Decryptor: For potential (but not guaranteed) decryption of specific Djvu variants.

4. Other Critical Information

  • Additional Precautions:
    • Information Stealer Module: Many Stop/Djvu variants, including 2ourt0, are often bundled with information-stealing malware (e.g., RedLine Stealer, Vidar Stealer, Azorult). This means that in addition to encrypting your files, the attackers may have stolen sensitive information such as browser credentials, cryptocurrency wallet details, system information, and other personal data. It is imperative to assume your personal information has been compromised and take steps to secure accounts (change passwords, enable MFA, monitor financial accounts).
    • Fake Decryptors: Be wary of fake decryptor tools advertised online. These are often scams designed to steal money or install further malware.
  • Broader Impact:
    • Data Loss & Operational Disruption: The primary impact is the loss of access to critical data, leading to significant operational disruption for individuals and businesses.
    • Financial Cost: This includes direct ransom payments (if chosen), recovery costs (IT services, new hardware), and lost productivity.
    • Reputational Damage: For organizations, a ransomware attack can severely damage reputation and customer trust.
    • Persistent Threat: Stop/Djvu’s continuous evolution and reliance on simple, effective social engineering tactics make it a persistent and widespread threat, particularly to individual users and small businesses who might not have sophisticated security measures.