Analysis Summary

Federal Civilian Executive Branch (FCEB) agencies in the United States have received an order from CISA to protect their servers against a vulnerability in VMware ESXi authentication bypass that is used in ransomware attacks.

With the release of ESXi 8.0 U3, Broadcom subsidiary VMware addressed this vulnerability (CVE-2024-37085), which Microsoft security researchers found on June 25. Attackers can add a new user to the 'ESX Admins' group using CVE-2024-37085. This group is not created by default but can be established after obtaining high privileges on the ESXi hypervisor. Once added, the new user will be granted full administrative access.

VMware classified the vulnerability as medium-severity, but Microsoft disclosed on Monday that multiple ransomware groups are already using it to escalate to full admin privileges on domain-joined hypervisors. Successful exploitation would still require user interaction and high privileges. After gaining admin access, they steal confidential information from virtual machines (VMs), travel laterally across the networks of their victims, and encrypt the file system of the ESXi hypervisor, which results in disruptions and interferes with business operations.

Ransomware operators tracked as Storm-0506, Storm-1175, Octo Tempest, and Manatee Tempest have so far used CVE-2024-37085 to spread the Akira and Black Basta ransomware. In response to Microsoft's revelation, CISA has added the security flaw to its list of "Known Exploited Vulnerabilities," indicating that threat actors may be using it in their attacks. Federal Civilian Executive Branch Agencies (FCEB) agencies now have three weeks until August 20 to safeguard their systems against ongoing CVE-2024-37085 exploitation.

The cybersecurity agency recommended all firms prioritize patching the hole and preventing ransomware attacks that could target their networks, even if this mandate is limited to federal agencies. These vulnerabilities represent serious threats to the federal organization and are commonly used as attack vectors by threat actors.

Since the victims began using their ESXi virtual machines (VMs) to host and store important apps and sensitive data, ransomware operations have been concentrating on attacking these VMs for years. But up until now, they have mostly relied on Linux lockers made to encrypt virtual machines instead of making use of certain security holes in ESXi (such as CVE-2024-37085), even if the latter would offer a quicker means of getting into victims' hypervisors.

Impact

• Privilege Escalation
• Unauthorized Access
• Financial Loss
• Sensitive Data Theft
• Operational Disruption

Indicators of Compromise

CVE

• CVE-2024-37085

Affected Vendors

Remediation

• Refer to VMware Security Advisory for patch, upgrade, or suggested workaround information.
• Organizations must test their assets for the vulnerability mentioned above and apply the available security patch or mitigation steps as soon as possible.
• Implement multi-factor authentication to add an extra layer of security to login processes.
• Regularly monitor network activity for any unusual behavior, as this may indicate that a cyberattack is underway.
• Organizations must stay vigilant and follow best practices for cybersecurity to protect their systems and data from potential threats. This includes regularly updating software and implementing strong access controls and monitoring tools.
• Develop a comprehensive incident response plan to respond effectively in case of a security breach or data leakage.
• Maintain regular backups of critical data and systems to ensure data recovery in case of a security incident.
• Adhere to security best practices, including the principle of least privilege, and ensure that users and applications have only the necessary permissions.
• Establish a robust patch management process to ensure that security patches are evaluated, tested, and applied promptly.
• Conduct security audits and assessments to evaluate the overall security posture of your systems and networks.
• Implement network segmentation to contain and isolate potential threats to limit their impact on critical systems.