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by schoen 3547 days ago
People making arguments about automata theory in security are often affiliated with the LANGSEC program/project/movement.

http://langsec.org/

There are lots of compelling ideas there (and LANGSEC researchers would tend to agree that if a functionality can be implemented correctly as an FSM, that would be a safer option).

A related phenomenon that people talk about is the unexpected Turing-completeness (where people have been able to prove that so many different parts of computing are Turing-complete -- things that were never intended to be programming languages). LANGSEC people and others refer to the negative security implications of some of this as "weird machines", where you really didn't want Turing-completeness but you got it by accident or by default anyway, and it might be possible for an attacker who can corrupt control flow or other kinds of state to then perform arbitrary operations. For security people an example may be return-oriented programming, but there are evidently others that can be thought of in the same way.

2 comments

Glad someone mentioned this. LANGSEC encourages you to think about computational power as privilege, and the principle of least privilege will guide you to constructing machines that are easier to reason about, leaving less room for ambiguity.
This is fascinating. Do you have any examples or stories of such 'weird machines'?
The concept is presented in

http://www.langsec.org/papers/Bratus.pdf

I think people have found a number of other, well, weird examples. I found

https://www.usenix.org/conference/woot15/workshop-program/pr...

via Google Scholar and there are more papers on this theme if you search for "weird machines" there. It seems like a helpful way to think about this issue!

At a higher level than the other guy, and not precisely the same thing:

http://blog.checkpoint.com/2016/02/02/ebay-platform-exposed-...

many thanks, peoples