wpfixes

Sorry, I meant I tried both plugins but not same time.

And all other plugins disabled. Also, tested with PHP 5.6, 7.0, 7.1, 7.2.

The issue is there with the latest version and an older version too (2.2.5).

Same problem, both plugins

Plugin could not be activated because it triggered a fatal error.

Fatal error: Uncaught Error: Call to a member function getNotices() on boolean in /home/public_html/wp-content/plugins/ultimate-social-media-icons/analyst/src/Mutator.php on line 31

Partially correct, hackers can login as administrator (first one if there are more) without entering username or password but they are uploading a little backdoor script (not detectable by any malware scanner) before that, using some vulnerable plugin or theme. WF is not catching that admin login meaning not sending email alert, no record in live traffic.

However, the problem I am interested in (and maybe many WF users) is if the admin login detection can be improved so these alerts are sent as usual. For now I added my custom code in theme/functions.php to fix that but would be nice to have WF catching it.

Funny. I had the same problem and looking for a solution. I found this fresh topic and that plugin worked for me.
Removing Jetpack’s Open Graph meta tags worked for me, thanks Jeremy.

For this problem check theme files, sometime header.php is totally replaced.

And they hide a javascript in database, wp_options table. Find and delete an option_name called widget_text, value beginning with:
<script>document.documentElement.innerHTML = unescape(''%3c%68%74%6d%6c%3e%0d%0a%3c%74%69%

If you have doubts about the content, deobfuscate here
https://www.patzcatz.com/unescape.htm

And of course do the rest… check you computer for trojans, update wp and plugins, change passwords, change Authentication Unique Keys and Salts in wp-config, backup etc