I appreciate your help!
Your wiki cannot be accessed currently, all it says is "Access denied".
Where does it say so? It works fine for me.
A bureaucrat _should_ be able to add and remove groups from users. This right can be restricted to certain groups, but it comes down to this: It is a question of trust that a bureaucrat does not abuse these rights.
Yeah I realised that after making the mistake.
If this user is not trusted, then he should be removed from the bureaucrat group.
I already did that.
Furthermore, you will need database access in order to remove the complete MediaWiki logs.
I know.
If the user "only" is a MediaWiki bureaucrat, then there is no way how he could remove log entries. He then can grant user rights through the MediaWiki interface and these actions will be logged. That is all.
I was just able to view your logs. The user in question deleted a number of pages and has hidden certain log information using the revision delete functions of MediaWiki. Looks like you had a vandalizing bureaucrat.
That’s EXACTLY what he did!
According to the Special:ListUsers page, it seems like you could fix the problem, right? The deleted pages are restored, the user is blocked and apart from him there only is one bureaucrat user now, who is called Admin.
Yeah I almost fixed the changes.
However I can’t unhide the deleted logs. The checkboxes are greyed out.
I’m glad my wiki prevents guest editing!