A Few Good Information Security Metrics

Andrew Jaquith says information security metrics don't have to rely on heavy-duty math to be effective, but they also don't have to be dumbed down to red, yellow, green. Here are five smart measurements--and effective ways to present them.

Not good for: Employee monitoring. Content surveillance is a different beast. In certain cases you may flag questionable content or monitor for it, if there's a previous reason to do this, but traffic analysis metrics aren't concerned with content except as it's related to the size of e-mails. A spike in large e-mails leaving the company and flowing to competitors may signal IP theft.

Added benefit: An investigations group can watch e-mail flow during an open investigation, say, when IP theft is suspected.

Try this: Monitor legitimate e-mail flow over time. CISOs can actually begin to predict the size and shape of spikes in traffic flow by correlating them with events such as an earnings conference call. You can also mine data after unexpected events to see how they affect traffic and then alter security plans to best address those changes in e-mail flow.

One possible visualization: Traffic analysis is suited well to a time series graphic. Time series simply means that the X axis delineates some unit of time over which something happens. In this case, you could map the number of e-mails sent and their average size (by varying the thickness of your bar) over, say, three months. As with any time line, explain spikes, dips or other aberrations with events that correlate to them.