I have a stored procedure which is part of a vendor supplied system. The stored procedure is encrypted so we can't see the code.

The stored procedure has all of a sudden started to run slow.

The first thing I would look to do is look at the execution plan to try to work out where the problem is, however, there doesn't seem to be a way to show the plan (sp_Whoisactive is NULL in the query_plan field)

I might also try to update statistics but I have no way of seeing what tables the stored procedure uses.

The wait stats for the query do not show anything obvious

Is it realistically possible to do any sort of troubleshooting on this query without having an un-encrypted version?