Re: Getting the value of an asset and the probability of a risk to it

[Jon Kibler <Jon.Kibler () aset com>]

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Sergio Castro wrote:
> Hi Philippe,
>
> The only true way of doing a quantitative risk assessment on an asset is using statistics. 
<SNIP!>

In theory, yes.

In reality, it just doesn't work that way.

For example: Historically, the chances of a Windows box on a secure
network getting rooted were less than 1 in 100,000. But if you use that
as a basis for computing future risk, I would argue that the historical
data has absolutely zero to do with reality today or in the future.

I would suspect that within the next 12 to 24 months, the chances of a
Windows box on a secure network getting rooted are about 1 in 1,000. So,
if you use statistics based on historical data, your risk assessment is
off by two orders of magnitude! (These numbers are for illustrative
purposes only! I just created these numbers by AE, but they are probably
within an order of magnitude of being correct.)

So, when projecting risk for the next 5 years, from where do you get the
data to form your statistical basis for risk?

Another example: A couple of years ago I heard Gadi Evron talk about
hardware rootkits (in BIOS, Video NRAM, NICs, Routers, etc.). Most
people laughed at the idea. And now, what is the big anticipated talk at
EusecWest? IOS Rootkits.

Again, how do you base risk on historical data, or do any type of risk
modeling when historical data is not applicable today and no one has a
reasonable guess for the future? To use statistics, it has to be based
on data. When historical data is not representative of current / future
risk, it is not a valid basis for forming statistical projections -- of
risk, or anything else for that matter.

As I said previously, it is essentially impossible in today's I.T.
security environment to do quantitative risk assessment that stands any
chance of passing the laugh test.

Except perhaps for risks associated with Mother Nature. And with climate
change, who knows how accurate those data will be?

Jon Kibler
- --
Jon R. Kibler
Chief Technical Officer
Advanced Systems Engineering Technology, Inc.
Charleston, SC  USA
o: 843-849-8214
c: 843-224-2494
s: 843-564-4224

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