Adversaries may abuse ESXi administration services to execute commands on guest machines hosted within an ESXi virtual environment. Persistent background services on ESXi-hosted VMs, such as the VMware Tools Daemon Service, allow for remote management from the ESXi server. The tools daemon service runs as `vmtoolsd.exe` on Windows guest operating systems, `vmware-tools-daemon` on macOS, and `vmtoolsd ` on Linux.(Citation: Broadcom VMware Tools Services) Adversaries may leverage a variety of tools to execute commands on ESXi-hosted VMs – for example, by using the vSphere Web Services SDK to programmatically execute commands and scripts via APIs such as `StartProgramInGuest`, `ListProcessesInGuest`, `ListFileInGuest`, and `InitiateFileTransferFromGuest`.(Citation: Google Cloud Threat Intelligence VMWare ESXi Zero-Day 2023)(Citation: Broadcom Running Guest OS Operations) This may enable follow-on behaviors on the guest VMs, such as File and Directory Discovery, Data from Local System, or OS Credential Dumping.
Detects anomalous usage of ESXi Guest Operations APIs such as StartProgramInGuest, ListProcessesInGuest, ListFileInGuest, or InitiateFileTransferFromGuest. Defender perspective focuses on unusual frequency of guest API calls, invocation from unexpected management accounts, or execution outside of business hours. These correlated signals indicate adversarial abuse of ESXi administrative services to run commands on guest VMs.