VMware Host VMX Process COM Class Hijack Privilege Escalation

The VMX process (vmware-vmx.exe) process configures and hosts an instance of VM. As is common with desktop virtualization platforms the VM host usually has privileged access into the OS such as mapping physical memory which represents a security risk. To mitigate this the VMX process is created with an elevated integrity level by the authentication daemon (vmware-authd.exe) which runs at SYSTEM. This prevents a non-administrator user opening the process and abusing its elevated access. Unfortunately the process is created as the desktop user which results in the elevated process sharing resources such as COM registrations with the normal user who can modify the registry to force an arbitrary DLL to be loaded into the VMX process. Affects VMware Workstation Windows version 14.1.5 (on Windows 10). Also tested on VMware Player version 15.

MD5 | 89f47ed75e40cece6cb2c49cd4ca6364

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