The plugin register. Used on 200,000+ sites
User Switching
No known security flaws are listed for User Switching at the moment. New ones are found every week, which is what the morning watch is for.
Is your site on a safe version?
Be told the day a new one is found.
Mendbird checks your site every morning against the lists of known flaws, and emails you in plain English the day one hits something you run. Free for 14 days, then £9 a month.