They definitely can blacklist the certificate.

They have the choice of having HTTPS effectively useless (by leaving the certificate there), or making HTTPS not work (by removing it, thus prompting action from the user to fix it -- perhaps by calling their tech savvy nephew).

Browser vendors should (and usually do) err on the side of security.

Or the users just switch to a browser that works. IE or Chrome :(

Most Firefox users switched away from those (or didn't switch to them) because it works better for them - including security wise. I suspect that won't be their first course of action.

One way would be to bypass the proxy if it's detected as a Superfish proxy by its certificate, but somehow I feel like this isn't a problem the browser vendors should be doing extra workarounds for (and giving precedence to "if we don't like your proxy we'll ignore it" isn't a great idea either.)

It doesn't appear to be implemented as a user visible proxy, it modifies the network stack. From:

https://twitter.com/matthew_d_green/status/56843703790644428...

Probably not a proxy; probably low-level socket interception in Windows.

So there isn't much the browsers can do to help the user.

At least the technical side of Lenovo's response is all the way to "We are writing a program to remove the certificates", which is probably the thing that is going to impact the most people.

That's not their problem. It's Lenovo who'll be getting the support calls for their defective, sorry, "enhanced" product

If the user installs a Firefox update and then all their HTTPS connections stop working, most users will blame Firefox unless the error messages are very specific about Lenovo's involvement, which simple blacklisting won't do. Users who follow technical news and understand the problem will already have removed the certificate manually (and removed the proxy).

I doubt it. Most non-techie users will probably not get around to installing another browser, so seeing that neither bank nor gmail nor facebook works, they'll blame their ISP.

But most people already have IE installed!

On the other hand, this is making the news.