First of all, this is my first question so excuse me if I'm a bit clunky. I'm currently using magento 22.214.171.124. On our production site, today we received 3 unathorized messages on our admin notification inbox. The content of the messages are not relevant, it's just gibberish. They aren't being pulled from any RSS feed i'm subscribed to. Someone is using this functionality to spam my site. What troubles me is the possibility that someone found a security hole and is trying to gain access to the server and/or database.
I'm no security expert and I don't really know how to approach the situation. First thing I did was a complete backup of the database and file system. Then I've checked the system and exception logs, but haven't found anything relevant.