Summary:
A newly enhanced version of the Qilin (Agenda) ransomware, dubbed 'Qilin.B,' has been detected in cyberattacks, showcasing stronger encryption techniques, improved evasion from security tools, and sophisticated methods to disrupt data recovery processes. Spotted by researchers at Halcyon, this Rust-based strain uses advanced encryption, including AES-256-CTR with AESNI support for faster encryption on modern CPUs, while retaining ChaCha20 for older or weaker systems, ensuring encryption remains effective on all hardware. Additionally, it incorporates RSA-4096 with OAEP padding for key protection, making decryption almost impossible without the private key or seed values.

Upon execution, Qilin.B adds an autorun key to the Windows Registry for persistence and terminates critical processes like Veeam (backup and recovery), Windows Volume Shadow Copy Service, SQL database services, Sophos antivirus, and Acronis Agent, effectively neutralizing security and backup tools. It also deletes existing volume shadow copies to prevent system restoration and clears Windows Event Logs, complicating forensic investigations. After encrypting data, the ransomware deletes its binary to avoid detection. Qilin.B targets both local directories and network folders, generating ransom notes for each directory processed, with victim IDs included in the titles. To maximize its reach, the ransomware modifies the Windows Registry to enable network drive sharing between elevated and non-elevated processes, allowing it to spread more easily across the victim's environment. Though these features are not entirely novel in ransomware, their integration into a notorious family like Qilin significantly increases the potential impact.


Security Officer Comments:
Sophos previously reported that Qilin ransomware deploys custom info-stealers to capture credentials stored in Google Chrome, enabling attackers to extend their reach across networks or reinfect compromised systems. Past Qilin attacks have caused significant damage, including incidents targeting major services. While Qilin also has a Linux variant focused on VMware ESXi, the newly discovered Qilin.B variant specifically targets Windows systems, displaying the threat actor's motivation to expand to multiple environments.


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.


Link(s):
https://www.bleepingcomputer.com/ne...cryptor-features-stronger-encryption-evasion/


https://www.halcyon.ai/blog/new-qil...oasts-enhanced-encryption-and-defense-evasion