> Fundamentally, if you control a domain you can get a CA-signed certificate for any label under it. It's worse than that. All an attacker needs to do is pass

> Fundamentally, if you control a domain you can get a CA-signed certificate for any label under it. It's worse than that. All an attacker needs to do is passively monitor the target domain's emails, and he can get a valid CA-signed certificate. If the attacker can only monitor some networks, not all globally: no problem, since the attacker gets to choose which CA the email gets sent from!