Original text by n00py
I’ll state this upfront, so as not to confuse: This is a POST exploitation technique. This is mostly for when you have already gained admin on the system via other means and want to be able to RDP without needing MFA.
Okta MFA Credential Provider for Windows enables strong authentication using MFA with Remote Desktop Protocol (RDP) clients. Using Okta MFA Credential Provider for Windows, RDP clients (Windows workstations and servers) are prompted for MFA when accessing supported domain joined Windows machines and servers.
This is going to be very similar to my other post about Bypassing Duo Two-Factor Authentication. I’d recommend reading that first to provide context to this post.
Biggest difference between Duo and Okta is that Okta does not have fail open as the default value, making it less likely of a configuration. It also does not have “RDP Only” as the default, making the console bypass also less likely to be successful.
With that said, if you do have administrator level shell access, it is quite simple to disable.
For Okta, the configuration file is not stored in the registry like Duo but in a configuration file located at:C:\Program Files\Okta\Okta Windows Credential Provider\config\rdp_app_config.json
There are two things you need to do:
- Modify the InternetFailOpenOption value to true
- Change the Url value to something that will not resolve.
After that, attempts to RDP will not prompt Okta MFA.
It is of course always possible to uninstall the software as an admin, but ideally we want to achieve our objective with the least intrusive means possible. These configuration files can easily be flipped back when you are done.