A Few Good Metrics

A Few Good Metrics

Mention metrics to a CIO or infosecurity executive and immediately their thoughts may well turn to sigmas, standard deviations and, probably, probability. To many, metrics equals statistics.

METRIC 5 Legitimate E-Mail Traffic Analysis

Legitimate e-mail traffic analysis is a family of metrics including incoming and outgoing traffic volume, incoming and outgoing traffic size, and traffic flow between your company and others. There are any number of ways to parse this data; mapping the communication flow between your company and your competitors may alert you to an employee divulging intellectual property, for example. The fascination to this point has been with comparing the amount of good and junk e-mail that companies are receiving (typically it's about 20 percent good and 80 percent junk). Such metrics can be disturbing, but Jaquith argues they're also relatively useless. By monitoring legitimate e-mail flow over time, you can learn where to set alarm points. At least one financial services company has benchmarked its e-mail flow to the point that it knows to flag traffic when e-mail size exceeds several megabytes and when a certain number go out in a certain span of time.

How to get it: First shed all the spam and other junk e-mail from the population of e-mails that you intend to analyze. Then parse the legitimate e-mails every which way you can.

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. CIOs 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.

METRIC 6 Application Risk Index

How to get it: Build a risk indexing tool to measure risks in your top business applications. The tool should ask questions about the risks in the application, with certain answers corresponding to a certain risk value. Those risks are added together to create an overall risk score.

Expressed as: A score, or temperature, or other scale for which the higher the number, the higher the exposure to risk. Could also be a series of scores for different areas of risk (for example, business impact score of 10 out of 16, compliance score of three out of 16, and other risks score of seven out of 16).

Industry benchmark: None exist. Even though the scores will be based on observable facts about your applications (such as, is it customer-facing? Does it include identity management? Is it subject to regulatory review?). This is the most subjective metric on the list, because you or someone else puts the initial values on the risks in the survey instrument. For example, it might be a fact that your application is customer-facing, but does that merit two risk points or four?

Good for: Prioritizing your plans for reducing risk in key applications - home-grown or commercial. By scoring all of your top applications with a consistent set of criteria, you'll be able to see where the most risk lies and make decisions on what risks to mitigate.

Not good for: Actuarial or legal action. The point of this exercise is for internal use only as a way to gauge your risks, but the results are probably not scientific enough to help set insurance rates or defend yourself in court.

Added benefit: A simple index like this is a good way to introduce risk analysis into information security (if it's not already used) because it follows the principles of risk management without getting too deeply into statistics.

Try this: With your industry consortia, set up an industry-wide group to use the same scorecard and create industry-wide application risk benchmarks to share (confidentially, of course). One industry can reduce risk for everyone in the sector by comparing risk profiles on similar tools. (Everyone in retail, for example, uses retail point-of-sale systems and faces similar application risks.)

One possible visualization: Two-by-two grids could be used here to map your applications and help suggest a course of action. Two-by-twos break risk and impact into four quadrants: low risk/low impact, low risk/high impact, high risk/low impact, high risk/high impact. A good way to use these familiar boxes is to label each box with a course of action and then plot your data in the boxes. What you're doing is facilitating decision making by constraining the number of possible courses of action to four. If you need to get things done, use two-by-two grids to push executives into decision making.

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