Windows 7 Boot Process and Configuration

Thwart virtual machine detection

How to thwart virtual machine detection:

For starters, do not install tools provided by the virtual machine in your guest OS. For example, VMware provides a set of tools called VMware Tools that enhances the overall user experience with the guest OS. The drawback is that installing VMware Tools in a Windows guest OS will leave many clues easily detectable by a piece malware that it is being run in a virtual machine.

The next step is to edit your VMware .vmx file. When you create a new virtual image with VMware, settings about it are stored in a configuration file with the .vmx extension. The file contains information about networking, disk size, devices attached to the virtual machine, etc...and is usually located in the directory where you created your virtual image. With your guest OS stopped, edit the .vmx file and append the following:

isolation.tools.getVersion.disable = "TRUE"
isolation.tools.getPtrLocation.disable = "TRUE"
isolation.tools.setPtrLocation.disable = "TRUE"
isolation.tools.setVersion.disable = "TRUE"
isolation.tools.getVersion.disable = "TRUE"
monitor_control.disable_directexec = "TRUE"
monitor_control.disable_chksimd = "TRUE"
monitor_control.disable_ntreloc = "TRUE"
monitor_control.disable_selfmod = "TRUE"
monitor_control.disable_reloc = "TRUE"
monitor_control.disable_btinout = "TRUE"
monitor_control.disable_btmemspace = "TRUE"
monitor_control.disable_btpriv = "TRUE"
monitor_control.disable_btseg = "TRUE"

Now start your virtual machine. This will allow you to run (with very little effort) more vmware-aware malware than before.

I'll point out that:

1. monitor_control.disable_directexec = "TRUE" will usually thwart descriptor table registers checks. This setting will make VMware interpret each assembly instruction instead of executing them directly on the processor. Therefore a the result of a sidt instruction will not be an address in the 0xffXXXXXX range as one would get without this setting.
2. isolation.tools.getVersion.disable = "TRUE" will thwart the backdoor I/O check.