topic Outbound RDP access in General Topics

Outbound RDP access

Amin2 — Sun, 03 May 2020 18:34:07 GMT

I just heard one of my coworkers saying we need to block outbound access to RDP, I didn't have chance to follow up with him what him because of COVID-19. I am trying to to understand what would be the reason, is that a best practice possibly?

Re: Outbound RDP access

reaper — Sun, 03 May 2020 22:19:43 GMT

RDP is a remote desktop protocol designed for internal use. It is uncommon for it to be run over the internet instead of more secure/flexible solutions (vpn, TeamViewer,...).

It's not as dynamic as the alternatives, so it is more likely a user connecting back to their home computer than a legitimate use by a contractor for example

Re: Outbound RDP access

Amin2 — Sun, 03 May 2020 23:11:22 GMT

So from your response, we should block RDP outbound probably using App-ID, would that be accurate?

Re: Outbound RDP access

BPry — Mon, 04 May 2020 02:08:41 GMT

@Amin2,

That solely depends on your use case and if its something that you wish to allow. In secure environments (think Banking, Hospitals, and other regulated industries) you would absolutely block ms-rdp connects to your untrust interface. The risk in allowing RDP connections to external resources comes more in data retention and access rather than it being inheritably insecure. It's an easy way at that point for data to be exfiled from your network either for malicious purposes or by a well-meaning technically savvy user. In these type of environments though, it's absolutely something you wouldn't want to allow.

In a more office centric environment where you don't have any regulatory compliance reasons to limit this access and didn't have a strong business need to secure data, then this is more of a policy decision. I would argue that your employees probably have no need to ever access any outside resources via RDP, and that it can safely be closed and requests to open access can be evaluated for business need on a case-by-case basis.

Essentially, unless you have a business need for this to be open to the outside work you provide a chance for data exfiltration that likely doesn't have a valid reason to be allowed.

Re: Outbound RDP access

Amin2 — Mon, 04 May 2020 04:22:58 GMT

Thank you very much for the explanation. I understood blocking inbound rdp connection but just didn't quite understand about outbound connection until your explanation, that cleared it up for me.

Best Regards

-Amin