Source of information 

The various log sources will help you to provide security events in different respects. Here are some of the general recommendations of the security monitoring focuses: 

Source of information	Security monitoring focuses
Application logs	These are the operational and error logs generated by the application. If the application is a web service, the logs may be included in Apache or nginx logs: Monitor the user activities, especially those activities that involve access to sensitive data Monitor the major changes of user profiles, such as login IPs, abnormal endpoint devices, non-browser connection clients, and concurrent connections from different IP sources Monitor the activities of administration and service accounts Monitor login failures and web errors, such as 401, 404, and 501
Host security, database logs	These mainly rely on the host-based IDS/IPS detection logs, OS, and database logs: Successful and failed authentication of users Administrative access and changes Unauthorized...