Hi AAC
There are only two locations in CyberAlarm where "Malicious activity detected" is thrown. Rebuilding the server isn't a solution... but without the code, they won't know why it's happening.
and...
If it's being thrown at 165, it's because the token (a CSRF token they added after one of my disclosures) isn't valid or present. If it's thrown at 665, it's the same reason... but related to the creation of logs.
For both situations, it's a sessions issue. Either the session cookie is expiring/being removed before the session has ended or it's not being created properly.
You could check your session.save_path INI setting to make sure it's able to write the session data to storage. If it can't, $_SESSION['token'] won't exist and it'll crash with that error. It could also be an FQDN issue... are you loading the console via IP or have you mapped a domain/subdomain to it? The session cookie will be tied to the FQDN and won't be valid if (when) CA tries to load over a different IP/FQDN.
In any event, as others have said, it's not worth running anyway. It's of no appreciable benefit; it's poorly written/insecure and only adds risk where it's not necessary.