First, companies need to monitor the right logs, including data from firewalls, virtual private networking (VPN) appliances, Web proxies and DNS servers. Next, the security team must collect data on what “normal” looks like inside the company’s network. Third, analysts must identify the indicators of attacks in their log files. Finally, the security group must have a procedure for responding to incidents identified by log analysis.
via Five Indicators To Watch For On Your Networks — Dark Reading.