FBI Confirms BianLian Ransomware Switch to Extortion Only Attacks
Cyber Security Threat Summary:
A recent collaboration between government agencies in the United States and Australia, led by CISA, has resulted in a joint Cybersecurity Advisory. The advisory highlights the latest tactics, techniques, and procedures (TTPs) employed by the BianLian ransomware group, which has been actively targeting critical infrastructure in both countries since June 2022. As part of the broader #StopRansomware initiative, this advisory draws on investigations conducted by the FBI and the Australian Cyber Security Centre (ACSC) up until March 2023. Its primary objective is to equip organizations with the necessary knowledge to adapt their security measures and fortify their defenses against BianLian.
Initially, Bian Lian adopted a double extortion approach, where they would first steal private data from targeted networks and then encrypt the systems, threatening to expose the files unless a ransom was paid. However, starting in January 2023, BianLian altered their tactics following the release of a decryptor for their ransomware by Avast. Instead, of encrypting systems, they shifted to a data-theft-based extortion method. This new strategy remains highly effective since it essentially constitutes data breaches, causing reputational harm to victims, eroding customer trust, and introducing legal complications.
Security Officer Comments:
According to CISA's advisory, BianLian gains access to systems by utilizing legitimate Remote Desktop Protocol (RDP) credentials, which they may have obtained by purchasing from initial access brokers or through phishing attacks. BianLian employs a custom backdoor written in Go, along with commercially available remote access tools, command-line utilities, and scripts for network reconnaissance. The final phase involves exfiltrating victim data through various means, such as the File Transfer Protocol (FTP), the Rclone tool, or the Mega file hosting service.
Suggested Correction(s):
The advisory recommends several measures that can help defend the network:
General Ransomware Mitigation: 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 how to avoid and spot phishing emails. Multi Factor authentication can help prevent malicious access to sensitive services.
Link(s):
https://www.bleepingcomputer.com/
https://www.cisa.gov/