Technology

That’s not how certificates work. In fact, the whole point of certificates is so a man in the middle can’t do that.

When you try to visit a website at for example websiteA.com, your browser will look at the cert it receives for the website and make sure it was signed by a trusted CA, which your browser keeps a list of locally. A MiTM could make a fake CA to sign their fake websiteA.com certificate with, but your browser would obviously have no record of that fake CA and wouldn’t trust it.

In order for the attack you’re suggesting to work, the attacker would have to gain access to your host itself and plant their fake CA cert on your computer. Or somehow compromise a real trusted CA which would be… a pretty huge deal.

You can't forge a root CA, unless you've found a way to break RSA or trick users into installing your malicious CA. The entire chain needs to be valid for browsers to accept it, all the way up to a root that the browser trusts. It's impossible for a CA to sign a cert but also not make it traceable to them.

If RSA gets broken, the entirety of Internet security would fall apart and the entire Internet would explode into complete chaos. Every SSH server would suddenly be broken wide open. All VPNs would be useless. Tor would be useless.

Which is why we have somewhat moved to quantum resistant crypto with elliptic curves to replace RSA, well before we actually manage to break RSA.