Help Needed with OpenFire Plugin and User Registration Issue

I have some issues with plugins; something happened with my OpenFire. I never installed this plugin, but it shows up every time I try to remove it. Does anyone know about this plugin? The name of this plugin is very strange—something like an encrypted name. Additionally, on the User Summary pages, I noticed that a couple of unknown users have been registered on my OpenFire server. These users have administrative privileges, even though I never installed any registration plugin.
I’m using Openfire 4.6.4. Could someone please help me with this issue?

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your installation may have been compromised.