The Num Lock or Caps Lock LED on your keyboard does not light up when using with a Belkin Secure KVM

Scenario:

The Num Lock or Caps Lock LED on your keyboard does not light up when using with a Belkin Secure KVM.

Explanation:

Standard USB keyboards and mice are a potential risk for signaling attacks upon critical cyber assets. Exposed USB ports can also be used to facilitate internal theft of sensitive information as well as the injection of malware onto high security systems the KVM may be connected to.

In order to safeguard network segmentation, NIAP PP3.0 certified KVMs and KMs isolate and filter the USB ports to allow for a uni-directional flow of HID data (from keyboard / mouse into the KVM and out to connected systems). All other data is blocked from being transmitted. Copying of data stored on connected servers through the KVM is also blocked as there is no communication path from the server to the USB port on the KVM.

In order for the Caps Lock or Num Lock LED lights to turn ON or OFF, the keyboard must send the appropriate command to the operating system and receive an acknowledgement back. As the return communication path is blocked, the LEDs will not turn ON.

NOTE: Even if the LED is not illuminated, the operating system will still be in Caps Lock mode or Num Lock mode if the key is pressed. As a visual indicator for the operator, some OEM versions of Windows® provide an on-screen pop-up message that indicates the Caps Lock or Num Lock status.