Dear Fi1osof,
I found your message about wordpress hacking in
https://modx.pro/security/15912
on Aug 23, 2018. The hacking code generates extenupdates.php and moban.html.
I was hacked in the same way and I'm in trouble.
Did you know how these got into WordPress?
Has a problem such as information leakage occurred?
I would be very glad if you could get some information.
Best,
Sicily