Can we log both access & content changes? If we implement CraftCMS, we would need logging of both access and publishing (both successful and failed attempts). The ability to change/remove those logs should not be available to those using the CMS. Is this available in core?
Craft does some basic logging in the form of when an entry was updated/created and the last time a user logged in and from what IP address, etc.  If you want anything more detailed than that, you'd need a plugin.  There is one called Audit Log that might do what you're looking for.