System Monitor (Sysmon) is a Windows system service and device driver that, once installed on a system, remains resident across system reboots to monitor and log system activity to the Windows event log. It provides detailed information about process creations, network connections, and changes to file creation time. By collecting the events it generates using Windows Event Collection or SIEM agents and subsequently analyzing them, you can identify malicious or anomalous activity and understand how intruders and malware operate on your network.
(Please note that the paper is a few years old and was therefore written for an older version of Security Onion.)
If you are shipping Sysmon logs via Winlogbeat, confirm that your Winlogbeat configuration does NOT use the Elastic Sysmon module. Security Onion will do all the necessary parsing.