Chromium suddenly starts downloading a binary blob

Jake says "The contents of the executable should also be scrutinized, but there is no real way to do that." Why isn't there a real way to do that? At the worst, assuming none of the free software alternatives works, it could be reverse engineered with IDAPro.

If the code is so obfuscated that that isn't tractable, then I would take it as a strong signal that something nefarious is present.