Hi @Skeer! Welcome to the community and LogicMonitor!
I'll start by giving the standard answers I give to questions like this. These aren't accusations, just meant to help guide your thinking around what to do in this case and other cases like it:
1. Have you searched through the installed DataSources in your portal to find out if any DataSources apply but aren't yet monitoring data because of missing credentials or some other reason?
2. Have you searched the exchange to find any DataSources that might cover what you're looking for?
3. If existing DataSource(s) don't exist, you may need to build it. The question then becomes, how do you know about the CRL outside of LM? Do you manually pull up a list? What metrics are you looking for? If you can "monitor" it manually, the task merely becomes figuring out how to automate that manual process.
I don't have enough deep knowledge about SSL/TLS to really understand the goal, but feel free to educate me. I know several power users out here have built various different certificate centric DataSources, and one of them may fit the bill.