People keep asking questions like
If the risk equation I use is Impact * Probability, when it comes to calculating the residual risk value do I still need to consider the impact of Loss of confidentiality, integrity and availability of the asset afterwards ? My understanding us that the probability value may decrease after applying some controls to mitigate the risk, but how does does the impact change?
Personally I don’t like the use of the generalization “Impact“. It hides details and it hides seeing where the control is being applied. Assets are often affected by more than one threat or more than one vulnerability. You really need to recalculate the whole thing over again after the controls have been applied – don’t try for short cuts.
I’d further suggest looking at
I discuss this kind of over-simplification at
- Planning means planning for success and for not-success (herdingcats.typepad.com)
Some people seem to be making life difficult for themselves with risk models such as “Impact * Probability” and as such have lead themselves into all manner of imponderable … since this model hides essential details.
I discuss the CLASSICAL risk equation in my blog
There is a good reason for, no make that MANY good reasons, for separating out the threat and the vulnerability and asset rather that just using “impact”.
Any asset is going to be affected by many
Any control will almost certainly address many assets and in all likelihood deal with many threats and vulnerabilities.
Any reasonable approach will try to optimise this: make the controls more effective and efficient by having them cover as many assets, threats or vulnerabilities as possible.
As such, the CLASSICAL risk equation can then be viewed as addressing residual risk – the probability AFTER applying the controls.
Sometimes I wonder why we bother …
“If nothing else, perhaps the frequency, audacity and harmfulness of
these attacks will help encourage Congress to enact new legislation to
make the Internet a safer place for everyone,” the Sony executive said.
“By working together to enact meaningful cybersecurity legislation we
can limit the threat posed to U.S. all,” he said.
It seems that this legislation focuses on the 3rd and not the first.
It might even be seen to discourage the second.
- Sony backs U.S. cybersecurity legislation (canada.com)
- DOD Website Sells Public On Cybersecurity Strategy (informationweek.com)
- Companies To Spend $130 Billion On Cybersecurity In 2011 (teamshatter.com)
- Obama to Introduce Cybersecurity Proposal (circleid.com)
- White House to unveil cybersecurity proposal (theglobeandmail.com)
- What do we need to do to reach “cybersecurity awareness”? (nakedsecurity.sophos.com)
- White House Cybersecurity Plan: What You Need To Know (huffingtonpost.com)
- Microsoft Endorses White House Cybersecurity Plan (blogs.wsj.com)