Microsoft is urging users of VMware’s ESXi hypervisor to take immediate action to ward off ongoing attacks by ransomware groups that give them full administrative control of the servers the product runs on.
The vulnerability, tracked as CVE-2024-37085, allows attackers who have already gained limited system rights on a targeted server to gain full administrative control of the ESXi hypervisor. Attackers affiliated with multiple ransomware syndicates—including Storm-0506, Storm-1175, Octo Tempest, and Manatee Tempest—have been exploiting the flaw for months in numerous post-compromise attacks, meaning after the limited access has already been gained through other means.
Full administrative control of the hypervisor gives attackers various capabilities, including encrypting the file system and taking down the servers they host. The hypervisor control can also allow attackers to access hosted virtual machines to either exfiltrate data or expand their foothold inside a network. Microsoft discovered the vulnerability under exploit in the normal course of investigating the attacks and reported it to VMware. VMware parent company Broadcom patched the vulnerability on Thursday.