Comment by jon-wood
3 years ago
One of the examples given wasn't a server name, it was leaking potentially confidential information via the domain olympics-campaign.staging.example.org - in many environments its fine if people know project names, but NDAs are a thing, and you could end up in hot water if you accidentally leak a partnership between two companies before it's been announced.
Well, if instead of making a lot of effort in hiding your names you just didn't, you wouldn't use a name like that.
Every single person that connects to any of your networks (very likely the sandboxed mobile one too) can find that name. Basically no place hides it internally. There is very little difference between disclosing it to thousands of the people that care the most about you and disclosing it to everybody on the world.
The other examples are better. Say a never-before-seen name appears, cisco520.internal.foo.bar. Suddenly, a well-formed email appears, “Re: Cisco Support Ticket #7779311” about some additional steps to provision your new appliance. It is trivial to automate that phish by crawling the CT log.
Is this valuable enough to resist every real advancement in network security since the late 00's? Because for each one of them it's certain that people will pop-up making a lot of noise about hidden server names.
It's mostly because of them that DNS is still not reliable. Well, at least this article isn't against certificate transparency, just about how to avoid it.
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