Security Incident Ratings Made Easy

Management likes numbers. They get the the warm fuzzies when numbers can be graphed in a way that they can quickly discern what's going on. Of course, if the numbers are bad, then they may not feel those warm fuzzies. In the IT security world, we try to provide useful numbers to show what a great job we're doing, but it's hard to quantify thwarted attacks -- other than relying on numbers from an IPS and anti-malware system.Rating systems for attacks and vulnerabilities have been around for a while, but most are crude, risk-based matrices that rate security incidents with high, medium, and low ratings for probability on one axis, and impact on the other. Otherwise, I haven't seen anything that rates incidents well until a recent post from Richard Bejtlich on the TaoSecurity blog.

I'm not going to rehash his rating scheme, but what I do want to bring attention to are two factors: the granularity of the 10-point scale and moving it into the high/medium/low categorization, and the use of vulnerability as a type of incident.

A couple of readers commented that having 10 levels was too granular, but I disagree. If you need to break ratings down to a high, medium, or low classification, then Richard offers the option of viewing 1-3 as low, 4-6 as medium, 7-9 as high, and 10 as game over. The granularity is good for better reporting later on. I personally like graphs that have a smaller scale and more points to graph than ones that are more jagged. I think it helps to pinpoint more subtle changes in the data over time.

Richard said his reasoning for including vulnerabilities as an incident type is that some of his businesses classify them as such, even though it goes against how traditional incident detectors and responders think. I have mixed feelings on this one. The incident responder in me wants to agree and say that vulnerabilities shouldn't be included, but the security pro in me who wears many hats says it should. Why?

For security teams who are small and do incident response, vulnerability scanning, and penetration testing, detecting vulnerabilities and dealing with incidents tends to blur. If their experience is like mine, you have one ticketing system to manage it all, so it's often easy to simply and have an incident type of vulnerability. In fact, sometimes the detection of the vulnerability leads to a determination that a true incident has occurred already as a result of the vulnerability.

For teams who already have a mature incident rating system, this may seem old hat, but for those of you who don't, it may be just what you're looking for. And, remember, you don't have to use it verbatim. You can mix it up and use it as you please so that it best fits your organization.

John H. Sawyer is a senior security engineer on the IT Security Team at the University of Florida. The views and opinions expressed in this blog are his own and do not represent the views and opinions of the UF IT Security Team or the University of Florida. When John's not fighting flaming, malware-infested machines or performing autopsies on blitzed boxes, he can usually be found hanging with his family, bouncing a baby on one knee and balancing a laptop on the other. Special to Dark Reading.