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Comment by colemickens | Hacker News Reader

Okay? I'm very familiar with that principle, but I don't understand how to take that statement and apply it to the situation at hand. No one has ever operated this computer except me (though I did enroll the corp wifi certs).

So again, how could I be MITM'd without being aware of it, given HSTS?

Yes, someone could have snuck in a hacked copy of Chrome Canary that exposes phony cert chain information... but that's not what we were talking about, and I don't think most IT departments have the sophistication required to pull that off.

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If you enrolled the wifi certs into your system certificate store, certificates signed by them ignore HSTS, for exactly this use case.

I can't find any information about this. Can you point me at some additional information? Thank you in advance!

Here's a good write-up on how to see if your company is listening in on your encrypted web traffic:

http://security.stackexchange.com/a/2920

(Note: MITM is just one way companies monitor employees, but by no means the only way. If your company provided your work computer to you, or if they installed anything on your BYOD computer, I would treat everything you do on that computer as cc'ed to your boss by default.)

I mean, that's how I MITM SSL traffic on a daily basis to do development.

None of that speaks to HSTS/Pinning... which is the feature meant to protect against this sort of thing. I'm specifically asking about how a company can bypass HSTS/Pinning without modifying my local browser.

Everything I'm reading indicates that's not possible.

https://developer.mozilla.org/en-US/docs/Web/Security/Public...

>Firefox (and Chrome) disable Pin Validation for Pinned Hosts whose validated certificate chain terminates at a user-defined trust anchor (rather than a built-in trust anchor). This means that for users who imported custom root certificates all pinning violations are ignored.

That last sentence is key. From Wikipedia: some browsers "disable pinning for certificate chains with private root certificates to enable various corporate content inspection scanners and web debugging tools. The RFC 7469 standard also recommends disabling pinning violation reports for such certificate chains."

Perfect! This is the missing link! Thank you for helping me understand.

What does that have to do with wifi certificates?

If you add CA certificates for the Wifi they probably (I'm not sure if you can tell it manually to not do that) are added to the system-wide trust store. IE and Chrome check that for CAs, Firefox will soon (https://bugzilla.mozilla.org/show_bug.cgi?id=1265113)

(all this for Windows, I believe the same is true for OS X, Linux depends on your specific your setup)

> If you add CA certificates for the Wifi they probably (I'm not sure if you can tell it manually to not do that) are added to the system-wide trust store.

Internet Properties -> Content -> Certificates -> Advanced

You're fine. It's people using company computers that are being monitored.

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