ARGH! Remote Desktop is broken! (and here’s how to fix it)

Microsoft Remote Desktop is an awesome way to connect to a remote computer system to perform work or system administration. We use it all the time, and we have countless customers who are using it as part of their day to day work.

Some customers have found that after installing the Windows Update released this week, they can no longer access Remote Desktop.

What Happened

Recently, a new security vulnerability was discovered in the CredSSP “module” inside Windows. This vulnerability may allow an attacker to gain access to a Windows System and execute code, even without a valid set of credentials. A fix was published as a hot fix by Microsoft, and in most cases this has been installed on server environments and the server has been rebooted.

The update released on 8th May for the full Windows platform now prevents connections if either the server or the client are not updated to protect against this vulnerability.

In some cases, the update may not have been installed in a server environment (for example due to a patch schedule policy. It’s also possible that a server may now be updated, but a client may not be updated (for example, an older version of Windows).

How to work around

The best course of action is to update the affected machines. That may not be possible, or may require a window to install and manage the update process that is not available. We have an automated tool that can deploy a workaround as well as an organisation wide policy we can apply in some cases.

The workaround for individual machines can be found on Microsoft’s Website. Our support team can also help you with this.