How to Decrypt Ransomhub Ransomware and Recover Data?

Ransomhub ransomware is a highly sophisticated strain of malware designed to encrypt data on compromised systems and demand a ransom in exchange for a decryption key. Here’s a detailed overview of Ransomhub ransomware, its operations, and steps for decryption and file recovery.

What is Ransomhub Ransomware?

Ransomhub ransomware emerged as a significant threat in February 2024 and operates as Ransomware-as-a-Service (RaaS). Ransomhub is characterized by:

1. Technical Structure and Capabilities:
   • Programming Language: Written in Golang, which is known for cross-platform compatibility.
   • Encryption Algorithms: Uses a combination of complex encryption protocols:
     • Asymmetric Algorithm: x25519 (a variant of Elliptic Curve Diffie-Hellman, enabling secure key exchanges).
     • Symmetric Algorithms: AES256, ChaCha20, and xChaCha20, all known for high levels of security.
   • Supported Systems: Targets Windows, Linux, ESXi (virtual machines), ARM, and MIPS architectures, making it versatile and capable of spreading across diverse networks.
2. Operational Structure:
   • Ransomware-as-a-Service (RaaS): Operated by a figure named Koley, Ransomhub offers ransomware tools to affiliates through the RAMP4U cybercriminal forum.
   • Affiliate Program: Affiliates handle ransom negotiations, data exchanges, and receive 90% of the ransom payments, while Koley retains 10%.
   • Propagation Techniques: Ransomhub has network propagation capabilities, allowing it to spread across devices within a network. It can operate in both “secure” and “local” encryption modes to evade detection by network security tools.
3. Tool Integration:
   • TDSSKiller: A legitimate tool by Kaspersky, repurposed by Ransomhub to disable Endpoint Detection and Response (EDR) on target systems.
   • LaZagne: A credential-stealing tool that harvests passwords from browsers, email clients, and databases.
4. Recent Developments:
   • Recently, affiliates from the well-known LockBit ransomware group joined Ransomhub, enhancing its resources and threat potential.

How to Decrypt Files Encrypted by Ransomhub Ransomware

If Ransomhub has encrypted your files, there are two main decryption paths: restoring from backups and using specialized decryptor tools. Here are the steps for each:

1. Restoration from Backups

• Locate a Clean Backup: The best approach to recovery is a malware-free backup from before the infection.
• Disconnect Infected Systems: Prevent further spread by isolating affected systems from the network.
• Use Anti-Malware Software: Fully remove any ransomware remnants before restoring your backup to avoid reinfection.
• Restore Files: Load the backup onto your cleaned system, ensuring the ransomware is not still present.

2. Using the Ransomhub Decryptor

If you lack recent or complete backups, the Ransomhub Decryptor offers an alternative recovery solution. This tool is specifically developed to decrypt files encrypted by Ransomhub ransomware, even in complex or mixed network environments.

Versions of the Ransomhub Decryptor:

• Windows Decryptor: Targets and decrypts Windows servers.
• Linux Decryptor: Decrypts Linux-based systems, including VMware ESXi servers.
• Network Decryptor: Designed for networks with both Windows and Linux systems, enabling a comprehensive decryption across all infected devices.

How It Works:

• Cloud-Based Decryption: The decryptor tool connects with powerful cloud-based servers that can bypass Ransomhub’s encryption algorithms without needing access to the private keys. This is crucial, as Ransomhub uses secure encryption (x25519 for key exchanges and AES256/ChaCha20 for data encryption) that is otherwise challenging to break.
• Compatibility: Supports the same encryption algorithms used by Ransomhub, ensuring effective decryption.
• Steps for Use:
  1. Install the Relevant Decryptor: Choose the version that aligns with your environment (Windows, Linux, or Network).
  2. Run the Decryptor: Connect the tool to the cloud servers and begin the decryption process. The tool identifies and decrypts files based on the algorithms Ransomhub has used.
  3. Review and Restore: Once decryption is complete, review files to ensure they are fully functional and restore them as needed.

Important Considerations:

• Use Only When No Backups Are Available: This option is ideal if backups are unavailable or outdated.
• Payment: The Ransomhub Decryptor may involve a service fee depending on the size of data and network complexity. For example, a UAE-based marketing company recently decrypted 800 GB of data for a fee of $5,000 USD in bitcoins.

Additional Steps to Prevent Re-Infection:

User Training: Educate your team on phishing and common infection vectors to prevent accidental downloads.

Update Security Software: Ensure anti-virus and anti-malware tools are updated to detect similar threats.

Network Security Audits: Regularly audit your network for vulnerabilities, especially if it includes both Windows and Linux systems.