This reminds me of a discussion a few months back from a BSD maintainer who had done a lot of volunteer work for AWS over the years. I think he might have even been the person who alerted them to the insecurity of IMDSv1. There was a sense that AWS might have had great talented developers at the time, but they clearly didn't really understand the domain of running a hypervisor service exposed to the public. This feels like a similar situation, where I'm sure they "test" what they know to test, in the way they know, but compared to a bank, well, it wouldn't surprise me the least if no one at AWS ever even thought to ask banks how they handle things like this. Instead of testing that a process works the way you specified it, you need to make sure you even have the right specification in the first place by consulting with prior art and ensuring whatever you translate into software reflects the legal reality of the process you're trying to encode.

There's a similar thing with physical processes. My wife works in geointelligence ground processing and encountered this when her system was expanded to support SAR collections instead of just visual spectrum. Software that passed all of its internal tests was passing nonsense collection parameters because the developers didn't understand the difference between energy collected to a sensor cell reflected from the sun versus energy reflected from your own active scan. The capabilities and limitations aren't the same. You can perform the same processing. The bits on disk won't care. But if the process you encode doesn't accurately correspond to the physics of reality, you're producing nonsense. Memory-safe, syntactically-valid nonsense, but nonsense nonetheless.

This seems to happen quite a bit with software companies.

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spydum 5 hours ago | parent [-]

I have bad news if you think banks are the pinnacle of cyber security practices...

Maybe some rare few are, but by and large they generally stink.

They tend to give that impression because they hire tons of auditors and panjandrum, to hassle their suppliers, but internally they are winging it like the rest of us.

	▲	antonvs 3 hours ago \| parent [-]
		The difference is that at bigger banks at least, they tend to throw more money at the problem. They'll have defense in depth with e.g. DMZs, proxies for ingress and egress, locked down workstations and browsers, etc., and a different team for each one of those domains. So while the actual "on the ground" picture may look suboptimal at any given point, overall it does make for security that in practice is much better than average. This is reflected in the actual security compromise statistics. Your money in a bank is a lot safer than, say, your credit card deals on file with many retailers.