Jumat, 02 Juni 2006

Risk-Based Security is the Emperor's New Clothes

Donn Parker published an excellent article in the latest issue of The ISSA Journal titled Making the Case for Replacing Risk-Based Security. This article carried a curious disclaimer I had not seen in other articles:

This article contains the opinions of the author, which are not necessarily the opinions of the ISSA or the ISSA Journal.

I knew immediately I needed to read this article. It starts with a wonderful observation:

What are we doing wrong? Is the lack of support for adequate security linked to our risk-based approach to security? Why can't we make a successful case to management to increase the support for information security to meet the needs? Part of the answer is that management deals with risk every day, and it is too easy for them to accept security risk rather than reducing it by increasing security that is inconvenient and interferes with business.

I would argue that management decides to "accept security risk" because they cannot envisage the consequences of security incidents. I've written about this before.

However, Donn Parker's core argument is the following:

CISOs have tried to justify spending resources on security by claiming that they can manage and reduce security risks by assessing, reporting, and controlling them. They try to measure the benefits of information security "scientifically" based on risk reduction. This doesn't work... I propose that intangible risk management and risk-based security must be replaced with practical, doable security management with the new objectives of due diligence, compliance consistency, and enablement.

I agree. Here is a perfect example of the problem:

One CISO told me [Parker] that he performs risk assessment backwards. He says that he already knows what he needs to do for the next five years to develop adequate security. So he creates some risk numbers that support his contention. Then he works backwards to create types of loss incidents, frequencies, and impacts that produce those numbers. He then refines the input and output to make it all seem plausible. I suggested that his efforts are unethical since his input data and calculations are all fake. He was offended and said that I didn't understand. The numbers are understood by top management to be a convenient way to express the CISO's expert opinion of security needs.

This is my question: what makes these shenanigans possible? Remember the risk equation (Risk = Threat X Vulnerability X Asset Value) and consider these assertions:


  • Hardly anyone can assess threats.

  • Few can identify vulnerabilities comprehensively.

  • Some can measure asset value.


As a result, there is an incredible amount of "play" in the variables of the risk equation. Therefore, you can make the results anything you want -- just as the example CISO shows.

It is tough enough to assign values to threats and vulnerabilities, even if time froze. In the real world, threats are constantly evolving and growing in number, while new vulnerabilities appear in both old and new software and assets on a daily basis. A network that looked like it held a low risk of compromise on Monday could be completely prone to disaster on Tuesday when a major new vulnerability is found in a core application.

Parker's alternative includes the following:

Due diligence: We can show management the results of our threat and vulnerability analysis (using examples and scenarios) by giving examples of the existence of the ulnerabilities and solutions that others have employed (not including estimated intangible probabilities and impacts). Then we can show them easily researched benchmark comparisons of the state of their security relative to other well-run enterprises and especially their competitors under similar circumstances. We then show them what would have to be done to adopt good practices and safeguards to assure that they are within the range of the other enterprises.

Bottom line: be as good as the next guy.

Compliance: We are finding that the growing body of security compliance legislation such as SOX, GLBA, and HIPAA and the associated personal and corporate liability of managers is rapidly becoming a strong and dominant security motivation...(The current legislation is poorly written and has a sledgehammer effect as written by unknowing legislative assistants but will probably improve with experience, as has computer crime legislation.)

Bottom line: compliance has turned out to be the major incentive I've seen for security initiatives. I am getting incident response consulting work because clients do not want to go to jail for failing to disclose breaches.

Enablement: It is easily shown in products and services planning that security is required for obvious and competitive purposes and from case studies, such as the Microsoft experience of being forced by market and government pressures to build security into their products after the fact.

Bottom line: this is the weakest argument of the three, and maybe why it is last. Microsoft may be feeling the heat, but it took five years and the situation is still rough. Oracle is now under fire, but how long will it take for them to take security seriously? And so on.

I think Donn Parker is making the right point here. He is saying the Emperor has no clothes and the legions of security firms providing "risk assessments" are not happy. Of course they're not -- they can deliver a product that has bearing on reality and receive money for it! That's consequence-free consulting. Try doing that in an incident response scenario where failure to do your job means the intruder remains embedded in a client's infrastructure.

As security professionals I agree we are trying to reduce risk, but trying to measure it is a waste of time. I am sad to think organizations spend hundreds of thousands of dollars on pricey risk assessments and hardly any money on real inspection of network traffic for signs of intrusions. The sorts of measurements I recommend are performance-based, as I learned in the military. We determine how good we are by drilling and exercising capabilities, preferably against a simulated enemy. We don't write formulas guestimating our defense posture.

This is not the last I have to say on this issue, but I hope to be boarding a flight soon. I commend The ISSA Journal for publishing an article that undermines a pillar of their approach to security. I bet (ISC)2 will also love Donn's approach. :)

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