I am considering purchasing a basic USB keyboard/mouse switching box in order to allow me to use the same keyboard and mouse with two different physical machines. This is similar to a KVM (keyboard video mouse) switch, but just for the input devices rather than the display as well.
The two devices I want to switch between are my highly secure main computer and a less-secure secondary laptop that I use for travel (hotel Wi-Fi, etc) and for browsing potentially insecure non-tech websites (eg: online furniture shopping, local businesses, etc).
The roles of these two machines are clearly separated, for example I do not log in to any valuable online services using the travel laptop, and I have a separate set of online accounts to use on it. I treat the machine as though it is definitely compromised.
I am aware that Belkin have a range of 'secure' switches that are NIAP listed and have passed various accreditations, however most of these are more expensive than consumer switches as they are designed primarily for business/government use.
One that stands out to me is the Belkin OmniView Secure Series: https://www.amazon.co.uk/dp/B000UNBNVW/, which has the following security features advertised:
- Listed by NIAP and pending NIAP Common Criteria validation to EAL 4
- Prevents data transfer between classified and unclassified computers
- Features no hot keys or OSD to prevent data from being stored on KVM Switch
- Non-reprogrammable firmware prevents tampering with KVM logic
- Provides full support for USB computers, keyboards, and mice
Are you just paying for the accreditation here or is there a legitimate security advantage over more basic consumer switches?
I know that using a USB switching box does not protect me from attacks against the peripherals themselves, such as a vulnerable keyboard controller, badusb, etc.
However, the bit that concerns me just by looking at the box is that there is a cable from both of my machines that connects to a central point. These machines are really supposed to be air-gapped from each other.
Are my security concerns valid/appropriate and do you think there is anything I have missed?
Could there also be a better solution to my problem?