In this quick post I would like to emphasize that by using Outbound filtering in Windows Defender Firewall with Advanced Security you can do some kind of “segmentation” without real segmentation that would include implementation of VLANs, moving of your management interfaces IP addresses to different segments, switches configuration, implementation of access lists / firewall rules between segments that we all know that takes a lot of time and effort.

Yes, you should do it but in the meantime while you are preparing for such project implement outbound firewall rules on your clients‘ and by doing so prevent lateral movement of potential hacker from infected / compromised machine to other machines in the neighborhood …

But even more importantly – prevent your clients’ machines to access devices / interfaces / protocols that they do not ever need.
For example – do your end users need to access switches management interfaces? Or servers out-of-band management cards? Or your UPS management interfaces? Or your servers (excluding RDP servers) on port tcp 3389? And finally (as this will be covered in the video) do your end users ever use Powershell to access network resources or download stuff from the internet by using cmdlet: Invoke-WebRequest (or something similar)?
Probably (hopefully) the answer is NO.
And Windows Defender Firewall with Advanced Security and its possibility to apply outbound rules to your clients will help you achieve such state in your network.

In this short video I am showing outbound firewall rules that prevent (only) Powershell (32/64 bit, ISE, not ISE and also the one accessed remotely via Powershell Remoting) to access the internet.
Powershell is a great tool that is often (as it is directly integrated in operating system) abused by people that do not have good intentions 🙂 So by misleading the users to click on something that triggers Powershell (as legit tool in Windows) and runs some scripts Powershell is able to download some extra malware from the internet.
By using this firewall rules at least we do not need to worry that malware will be delivered by some Powershell script. 🙂 By following this example you can create your outbound firewall rules that can increase security of your endpoints.