Saturday, April 15, 2017

VEP: When disclosure is not disclosure.

True story, yo.

I want to tell a personal story of tragedy and woe to illustrate a subtle point that apparently is not well known in the policy sect. That point is that sometimes, even when an entire directory of tools and exploits leaks, your bugs still survive, hiding in plain sight.

A bunch of years ago, one of my 0days leaked in a tarball of other things, and became widely available. At the time, we used it as training - porting it to newer versions of an OS or to a related OS was a sort of fun practice for new people, and also useful.

And when it leaked, I assumed the gig was up. Everyone would play with it, and not just kill that bug, but the whole technique around the exploitation and the attack surface it resided in.

And yet, it never happened. Fifteen years later only one person has even realized what it was, and when he contacted us, we sent him a more recent version of the exploit, and then he sent back a much better version, in his own style, and then he STFU about it forever.

I see this aspect in the rest of the world too - the analysis of a leaked mailspool or toolset is more work than the community at large is going to put into it. People are busy. Figuring out which vulnerability some exploit targets and how requires extreme expertise and effort in most cases.

So I have this to say: Just because your adversary or even the entire world has a copy of your exploit, does not mean it is 100% burnt. And you have to add this kind of difficult calculus to any VEP decision. It happens all the time, and I've seen the effects up close.

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