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Comment by pmontra | Hacker News Reader

From the article

> “The false assumption is that most SSL implementations return the server time,” Simen said. “This was probably true in a Microsoft-only ecosystem back when they implemented it, but at that time [when STS was introduced], OpenSSL was already sending random data instead.”

And they link the reason for sending random data at https://mailarchive.ietf.org/arch/msg/tls/_clS-TIIlZUcid_2S4...

The post starts with

> Here's something I wrote about removing a fingerprinting opportunity from the current TLS protocol.

So the point is not that it was a bad idea, it is that MS didn't keep up with the world and didn't respond to requests from their customers to fix the problem.

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But, their _starting position_ is that they can't trust the network

> “Since the device is not in a state to communicate securely over the network, it cannot obtain time securely over the network as well, unless you choose to ignore network security or at least punch some holes into it by making exceptions.”

So, because they can't trust the network, or the time, they instead choose to randomly trust some of the requests over the network.

But it's okay because they rely on the certificate from that request to report whether it has been revoked or not.

Yes, I read that.

I think that if you're making mission-critical systems rely on nonguaranteed behavior from systems you don't control, then it's a Bad Idea.

The point is that it was guaranteed behavior before the spec was changed. As an aside, I do find it amusing that the memo was co-authored by a Googler. Google has the best fingerprinting & tracking tech baked into their core products. I guess they don't want competition! :)

https://www.ietf.org/archive/id/draft-mathewson-no-gmtunixti...

Ah, right you are. My brain wasn't letting that sink in yesterday.

Yeah, when I read about SSL returning the server time I thought of fingerprinting, and I'm glad to see that it was removed. The reason giving for using it – PRNG completely broken – gave me a WTF moment, too. A broken PRNG is gonna cause a lot more trouble in SSL (TLS) than a non-random random field.

I mean it still seems like a bad idea

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