Summary:
Researchers at Artic Wolf Labs have released details on a new ransomware variant dubbed ‘Fog” that has been targeting the networks of US organizations in the education and recreation sectors since May, 2024. In one of the incidents observed, Fog ransomware actors performed pass-the-hash attacks to gain access to administrator accounts and further establish RDP connections to Windows servers running Hyper-V and Veeam. In another attack, researchers spotted the actors deploying credential stuffing attacks to conduct lateral movement across the targeted environment. In each of these cases, the actors were able to gain access to victim environments by leveraging compromised VPN credentials from two different VPN gateway vendors.

Security Officer Comments:
The targeting of VPN credentials is a common tactic employed by ransomware actors to gain access to victim environments and move laterally to compromise systems and data of interest. These credentials are typically acquired from past data breaches or in malware campaigns involving the use of info-stealers. In the latest campaign, the actors were observed using their access to deploy Fog ransomware and encrypt files, which were further appended with the '.FOG' or '.FLOCKED' extensions. Like any other ransomware strain, Fog is capable of disabling antivirus solutions (e.g. Windows Defender) to prevent detection. It will also encrypt VMDK files in Virtual Machine (VM) storage and delete backups from object storage in Veeam and Windows volume shadow copies, making recovery difficult. Currently, Fog ransomware does not have a data leak site. However, a link to a Tor dark website used for negotiation is included in the ransom note left behind on the victim’s system. Researchers note that the actors behind Fog ransomware are interested in quick payouts as opposed to the more complex attacks involving data exfiltration and a high-profile leak site.

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 how to avoid and spot phishing emails. Multi Factor authentication can help prevent malicious access to sensitive services.

Link(s):
https://arcticwolf.com/resources/blog/lost-in-the-fog-a-new-ransomware-threat/