How good is risk assessment? Can a risk assessment actually identify all the risks that might plague a particular project, program or system? The short answer is no, not entirely.
Since humans became sentient and gained the ability to reason, we have been using our logical ability to attempt to see into the future and determine what may be coming next. We see what is going on around us, we remember what has happened in the past, we learn what others have experienced and we use that information as our guide to calculating the future. And that paradigm has served us well, generally speaking. We have the logical ability to avoid previously made mistakes and predict future trends pretty well. However, we never get it 100% right. It is a truism that no system ever designed to protect ourselves and our assets has not been defeated sooner or later. That is why a risk engineer will never tell you that their security measures will provide you with a zero-risk outcome. All you can do is lessen risk as much as possible.
One reason for this is an imperfect understanding of all the factors that contribute to risk for any given system or situation. These factors include understanding exactly what we are attempting to protect, understanding threats that menace the asset, understanding mechanisms that we have in place to protect the asset and understanding weaknesses that those threats may be able to exploit to defeat our protection mechanisms. If any one of these factors is imperfectly understood and integrated with the other factors involved, risk cannot be wholly eliminated.
Understanding what we a trying to protect is the factor that is easiest to accomplish usually, especially if it is something simple like money or our home. However, even this task can become daunting when you are trying to entirely understand something as complex as a software application or a computer network. These sorts of things are often composed of parts that we ourselves have not constructed, such as standard bits of code or networking devices that we simply employ in our bigger design but do not have a complete understanding of.
Understanding threats that menace our assets is more difficult. We are pretty good at protecting ourselves against threats that have been employed by attackers before. But the problem lies in innovative threats that are entirely new or that are novel uses and combinations of previously identified threats. These are the big reasons why we are always playing catchup with attackers.
Understanding the mechanisms we have in place to protect our assets is another area we can accomplish fairly well, but even this factor is often imperfectly understood. For example, how many of you have purchased a security software package to protect your network, but then have trouble getting it to work to its greatest effect because your team doesn’t have a handle on all of its complexities? We have seen this often in our work.
Finally, understanding weaknesses in our protection mechanisms may be the hardest factor of all to deal with. Often, security vulnerabilities go unrecognized until some cleaver attacker comes up with a zero-day exploit to take advantage of them. Or sometimes simple vulnerabilities seem easy to protect against until someone figures out that you can string a few of them together to affect a big compromise.
So, to get the most out of risk assessment, you need to gain the greatest understanding possible of all the factors that make up risk. In addition, you need to guard against complacency and ensure that you are not only protecting your assets to the greatest extent your ability and budget will allow, but you need to be prepared for those times that your efforts fail and security compromise does occur.