Summary:
Researchers at Group-IB have released a new blog post, providing a detailed analysis of RansomHub, a prominent Ransomware-as-a-Service (RaaS) operation that surfaced in early 2024. Built on the foundation of the defunct Knight (formerly Cyclops) ransomware, RansomHub offers a highly adaptable encryptor capable of targeting a broad range of systems, including Windows, Linux, FreeBSD, ESXi, and ARM-based architectures. This cross-platform flexibility enables affiliates to target a wide range of corporate environments, including local and remote file systems accessed via SMB and SFTP protocols. RansomHub’s encryptor is also engineered with advanced evasion techniques, such as rebooting into Safe Mode to bypass security software and systematically deleting backups and virtual machine snapshots, thereby increasing the pressure on victims to comply with ransom demands.

What sets RansomHub apart is its operational model and focus on attracting skilled affiliates. It offers one of the lowest commission fees in the RaaS landscape, initially only 10%, later increased to 15%, far below the typical 20–30% cuts taken by groups like LockBit. This generous revenue split, combined with a robust and intuitive affiliate portal, extensive documentation on how to extort victims effectively, and flexible options like using personal wallets, has attracted skilled affiliates from disrupted groups such as LockBit, ALPHV, Scattered Spider, and Evil Corp. Affiliates are equipped with tools to manage negotiations directly, including live-chat interfaces with victims and detailed playbooks on extortion tactics, ranging from pricing ransoms based on a company’s revenue to leveraging regulatory threats (e.g., GDPR or PIPL violations) to compel payment. Overall, this blend of technical sophistication and operational efficiency helped RansomHub quickly establish itself as a dominant force in the ransomware landscape.

Security Officer Comments:
A notable development is that RansomHub unexpectedly shut down its online infrastructure on April 1, 2025. Since then, activity from the group has come to a halt, with RansomHub nowhere to be seen. In the wake of RansomHub’s disappearance, researchers note that Qilin ransomware experienced a significant surge in both activity and disclosures. Just days before RansomHub’s blackout, Haise, one of Qilin’s administrators, began advertising updates on the RAMP forum, including a new version of the ransomware released on April 1st, along with a newly added DDoS feature for affiliates. Qilin's disclosure rate also saw a notable increase, with 48 companies reported in February, 44 in March, and 45 in early April, compared to fewer than 23 per month from July 2024 to January 2025. This sharp rise in activity, coupled with Haise's continued presence on the forum and the evident restructuring of Qilin’s operations, suggests that many former RansomHub affiliates may have transitioned to Qilin, contributing to its rapid expansion. The timing of these events points to a possible connection between RansomHub’s abrupt disappearance and the subsequent rise of Qilin ransomware.

Suggested Corrections:
Backup your data, system images, and configurations, regularly test them, and keep the backups offline: Ensure that backups are regularly tested and that they are not connected to the business network, as many ransomware variants try to find and encrypt or delete accessible backups. Maintaining current backups offline is critical because if your network data is encrypted with ransomware, your organization can restore systems.

Update and patch systems promptly: This includes maintaining the security of operating systems, applications, and firmware in a timely manner. Consider using a centralized patch management system; use a risk-based assessment strategy to drive your patch management program.

Test your incident response plan: There's nothing that shows the gaps in plans more than testing them. Run through some core questions and use those to build an incident response plan: Are you able to sustain business operations without access to certain systems? For how long? Would you turn off your manufacturing operations if business systems such as billing were offline?

Check your security team's work: Use a 3rd party pen tester to test the security of your systems and your ability to defend against a sophisticated attack. Many ransomware criminals are aggressive and sophisticated and will find the equivalent of unlocked doors.

Segment your networks: There's been a recent shift in ransomware attacks – from stealing data to disrupting operations. It's critically important that your corporate business functions and manufacturing/production operations are separated and that you carefully filter and limit internet access to operational networks, identify links between these networks, and develop workarounds or manual controls to ensure ICS networks can be isolated and continue operating if your corporate network is compromised. Regularly test contingency plans such as manual controls so that safety-critical functions can be maintained during a cyber incident.

Train employees: Email remains the most vulnerable attack vector for organizations. Users should be trained on how to avoid and spot phishing emails. Multi-factor authentication can help prevent malicious access to sensitive services.

Implement multi-factor authentication (MFA): External-facing assets that leverage single-factor authentication (SFA) are highly susceptible to brute-forcing attacks, password spraying, or unauthorized remote access using valid (stolen) credentials. Implementing MFA enhances security and adds an extra layer of protection.

Link(s):
https://www.group-ib.com/blog/ransomware-debris/