Defender UI broke after fixing vulnerability by updating plugins

Strange site link attached to my about us page seems like a hack. If you click the about us page on the front-end it redirects to a strange link.

The issue disappeared after I updated all the older plugins to the latest version as suggested by your agent.

But after the updates Defender admin screens are broken. I tried uploading the site files but that did not help.

At the time of my older plugin updates Defender was running a file scan. It seems to be showing 12 issues but could not check them as the screen is broken.

Please fix the UI and also configure the plugin to harden the security.