bap

I use OCaml at work. We work with the Binary Analysis Platform https://github.com/BinaryAnalysisPlatform/bap which is a pretty essential part of what we do. In general, OCaml seems somewhat popular in the area of compilers and program analysis. Facebook Infer is written in OCaml for example https://fbinfer.com/. This may be as you said because of these areas sometimes more academic flavor. There are companies out there using OCaml for all sorts of things, although of course it is a small fraction of those using python or C++.

Going to drop a toplevel comment and say while this is interesting (sincerely!) if people are interested in deeper tools/techniques the book Practical Binary Analysis is excellent, it ends in taint checking, symbolic excution techniques and uses Pin. https://practicalbinaryanalysis.com/ Also worth checking out is BAP, the Binary Analysis Platform, which is the successor project to Bit Blaze, and is one of the most fascinating binary analysis frameworks out there for my money. It was the only one of the darpa CGC entries that ran on real binaries, not the much less complicated ones developed specifically for the challenge. https://github.com/BinaryAnalysisPlatform/bap