[langsec-discuss] Breaking X.509 cert validation with frankencerts

travis+ml-langsec at subspacefield.org travis+ml-langsec at subspacefield.org
Wed Apr 9 20:32:04 UTC 2014

On Sun, Apr 06, 2014 at 08:26:41PM +0200, Meredith L. Patterson wrote:
> Oh, that's clever. I'd been headed down the symbolic-execution path for
> X.509 parse tree differentials, but GA fuzzing bred from real-world certs
> and synthetic cert parts is both hilarious and clearly effective. I wonder
> if we should invite them for an afternoon presentation, if they'll be
> around in time.

On the off chance you didn't already know this, mutation and
recombination of valid inputs are pretty much the standard "dumb"
fuzzing technique these days.  5 lines of python for the former:


There's a reasonable book on the subject that has sat unopened on my
desk but has pointers to lots of tools:


The main difficulty seems to be in setting up the test harness and
configuring a (private?) cloud of (presumably Linux) boxes to run it.

Microsoft seems enthusiastic:


Codenomicon has Testing as a Service:


And they found a prior TLS bug that way:

Remediating... like a BOSS.
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