I heard an interesting question the other day: What’s the difference between a vulnerability scanner and a SIEM? Qualys and Nessus are examples of vulnerability scanners. Arcsight and Splunk are examples of SIEMs.
To a security practitioner, the tools couldn’t be much more different, but not everyone is a security practitioner.
On a basic, fundamental level, a vulnerability scanner deals in what’s missing in the environment and what could happen as a result of those things that are missing. A SIEM deals in what actually has happened and is happening.
Every once in a while the NSA or another government agency releases a whitepaper with a lot of really good security advice. This paper on spotting adversaries with Windows event logs is a fantastic example. It’s vendor-neutral, just talking about Windows logs and how to set up event forwarding, so you can use the advice with any log aggregation system or SEIM. I just happen to use and recommend Splunk. But whatever you use, these are the workstation events you want to be logging.
I want to call your attention to a couple of items in the paper. Most breaches begin on workstations, and this paper has the cure.