packages/Net/UserAgent/Detect/APC.php flagged as malicious by Wordfence Firewall
What I believe it's flagging based on the "description" line in your post is probably that the UserAgent tool could be used by bad people to get information about a browser, possibly to look for versions or configurations with known security holes to exploit. But it doesn't seem to be used in CiviCRM as far as I can see, and the APC.php subclass file all it does is store the results in the APC cache if you're using that. I wonder if the whole Net/UserAgent folder could be removed from Civi.

UPDATE: It looks like the file will be removed in civi version 5.22: https://github.com/civicrm/civicrm-packages/pull/272