What's the alternative? There is no difference on the wire between a self-signed certificate for a site that simply doesn't care about certificates, and a self-signed certificate that is the sole marker of an attacker having hijacked the TLS connection of a site that very much does care about its security. A MITM attack looks identical on the wire to a self-signed cert.
Most self-signed sites are fine, but because a few are MITM attacks, they should all throw big warnings (which users will learn to ignore, because of poor signal-to-noise).
Most unencrypted sites are fine, but because a few are attack sites, ....
The criteria for a user to enter sensitive info should not be "the connection is encrypted" or even "the connection is encrypted and goes to the server it says it does", but "I know the real-world identity of who I'm talking to".
The criteria to warn the user against entering sensitive info should be the negation of that; "I don't know the real-world identity of who I'm talking to".
The means of warning the user, should be such that the user does not need to act when not trying to enter sensitive info. So rather than pop-ups or interstitials that have to be dismissed -- and that the user can learn to dismiss -- there should be some persistent UI cue (like the green "Citigroup Inc (US)" beside the address bar) that the user can check when needed.
Browser: "Bad cert! The world's gonna end!"
User: "That's just a discussion forum, I don't care."
Browser: "Bad cert! The world's gonna end!"
User: "That's Joe's blog, I don't care."
Browser: "Bad cert! The world's gonna end!"
User: "yeah yeah, that's nice"
Browser: "Bad cert! The world's gonna end!"
User: "Would you shut up already!"
User: "...Why is my bank account empty!?"The warning isn't about the site; it's about the connection.
Yes. Which is a bad idea. It conflates an absence of network shenanigans with "the user knows who he's talking to".
> it's attackers who intercept TLS connections to online
> banks and swap out the Verisign certificate with a self-
> signed certificate
You're saying that users can distinguish between the following possibilities:
- A site is over http, so it's insecure (and no big red warning).
- A site is over possibly compromised https with a big red warning, so it's insecure.
- A site is over verified https with a big green "everything is ok" light, so it's secure.
You seem to think that the average user knows that HTTPS needs a "red light/green light" system, but HTTP does not (because it's inherently insecure). I posit that the average user doesn't 'get' the difference between http with no warning and https with a green light. Why not have a system that is simple for the end-user? E.g.:
- green light == secure
- no green light == insecure
- no need to differentiate between http/https for
the average end-userHow about adding another signal? It sounds like you're arguing with the sea, expecting normals to change.
Use the recent https-only header that says "if you ever see an insecure connection to this site, it's a bug", and pre-populate the list.
Stop assuming that users will eventually get it, and design a better product.
It doesn't matter. The ONLY thing HSTS does is tell the browser to make future requests over HTTPS. If an HSTS site switches to a self-signed cert between my visits, the browser will still get warn me, because the new cert is suspicious.