Overview

VMware ESXi contains an authentication bypass vulnerability. A malicious actor with sufficient Active Directory (AD) permissions can gain full access to an ESXi host that was previously configured to use AD for user management by re-creating the configured AD group ('ESXi Admins' by default) after it was deleted from AD.

Description

Microsoft has uncovered a vulnerability in ESXi hypervisors being exploited by several ransomware operators to obtain full administrative permissions on domain-joined ESXi hypervisors. ESXi is a bare-metal hypervisor that is installed directly onto a physical server and provides direct access and control of underlying resources. ESXi hypervisors host virtual machines that may include critical servers in a network. In a ransomware attack, having full administrative permission on an ESXi hypervisor can mean that the threat actor can encrypt the file system, which may affect the ability of the hosted servers to run and function. It also allows the threat actor to access hosted VMs and possibly to exfiltrate data or move laterally within the network.

Impact

Successful exploitation of this vulnerability may allow a remote attacker to take control of the affected system and can encrypt the file system.

Solution

Users and administrators of affected product versions are advised to update to the latest version immediately

References

• 1. https://support.broadcom.com/web/ecx/support-content-notification/-/external/content/SecurityAdvisories/0/24505
• 2. https://www.microsoft.com/en-us/security/blog/2024/07/29/ransomware-operators-exploit-esxi-hypervisor-vulnerability-for-mass-encryption/
• 3. https://www.rapid7.com/blog/post/2024/07/30/vmware-esxi-cve-2024-37085-targeted-in-ransomware-campaigns/