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)