We provided you the heads up about the Microsoft "Exploitability Index" a couple of months ago when the software company announced the new index, designed to predict the likelihood its security vulnerabilities would be attacked. It's an interesting idea, but will it have much value for practitioners?This month's patch Tuesday, which is tomorrow, will be when Microsoft first attaches this exploit index to its current threat ratings. Threat ratings, as you probably know, are ranked in a series of "low" through "critical" depending on the nature of the flaw. This is how the exploitability index will look, from a story that detailed Microsoft's announcement:

1) Consistent Exploit Code Likely 2) Inconsistent Exploit Code Likely, and 3) Functioning Exploit Code Unlikely

The first one means a software flaw could be attacked with highly predictable results, and would probably be very easy to exploit. This would be very bad, as exploits would surface, and would be turned into weapons for mass use. This would be a critical vulnerability, and would need to be patched. Designation two could be bad, or it could be not-so-bad. Maybe an attacker could create an exploit, maybe not. And how the at-risk system reacts to the attack may not be very predictable. The third designation, Functioning Exploit Code Unlikely, is obvious: Microsoft has determined that developing a useful, functional attack tool would not be likely.

My opinion from back then hasn't changed from my original post, which is that this won't be of much value to operations teams trying to assess their risk. Tomorrow, and in the months ahead, we'll see if it works as intended.