Windows Defender Firewall with Advanced Security – what is that Advanced Security part? Let’s remove the dust … (Part 3 – Allow the connection if it is secure rules and Connection security rules (IPSec))

That advanced security part in Windows Defender with Advanced Security is the part that covers creation of “special” rules that are similar to Allow rules but only if it is secure and work in conjunction with Connection security rules (that should be configured separately).

Let say that you would like to implement PAW or Jump Box or just limit admins to (even mistakenly) connect to some machines – well Allow the connection if it is secure kind of rules can help you out.

In my example I decided to have two admins: Bill and John they are using same PAW or Jump box called C2 from where they connect to web interface for management of server called SRV2 (it is an empty IIS website – but just to get the idea …).

By following previous tutorials I needed to create firewall rule to allow port 80 to be accessible as local rules are not processed (and we know that in Windows Server, when you install a Role or Feature, firewall rules are automatically created…).

When I do so I am able to access website on http://srv2 from machine C2 if John or Bill are logged in. But what if only Bill is the admin that should access http://srv2 web interface – can we somehow limit that feature for John? The answer is YES!

So first of all we need to create a new Group Policy Object where we will make a Block rule on port 80 – so nobody in the company will be able to access web service on SRV2 any more. After that we will create a new rule where we will chose the option: Allow the connection if it is secure – and as requirement for a successful connection will be that user on the machine should be Bill and machine where Bill is connecting from our PAW or Jump Box called C2. No other combination will fulfill the criteria. So if John is connected to C2 it is a wrong user. If Bill is connected to C1 and would like to do a connection a wrong computer is in use… So only valid combination of valid user and valid computer can fulfill the criteria and allow the connection. Just imagine how granularly you can configure which admin can do or access RDP / Powershell remoting, connect via MMC and other consoles… First of all we reduce potential mistakes that can be done but we are making it also difficult for potential hacker to get all the prerequisites to establish a successful connection …
After that we need to create another Group Policy object where we will define Connection security rules – basically we will make PAW or Jump box in our case called C2 establish IPSec connection to SRV2 when user will try to open webpage (on TCP port 80).

Here is the video of such scenario:

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