Comment by dannyw
4 hours ago
Yes, I'm assuming network MITM and DPI.
The whole point of TLS and certificates is to counter network MITM attacks.
Browsers and clients emit a lot of fingerprints, you can probably figure it out loosely from the TLS initialisation.
So let’s take a step back and look at this threat model.
1) An attacker is MITMing your connection. This is already not easily exploitable by most threat actors short of being on a public Wi-Fi network, otherwise you are likely at the nation-state level attacker at this point.
2) An attacker knows exactly which Git repo you’re about to clone and has prepared a malicious version (noting they can’t snoop on your encrypted web traffic).
3) An attacker has developed a way to differentiate between Git over HTTPS and Safari, by using a side channel “fingerprinting” method that works with your exact versions of git and macOS.
4) You don’t pin the git clone to a particular hash or signature.
This is already a very low level of exploitability. All of these things need to be satisfied for the attack you’re describing to work.
Now let’s look at a more practical attack that exists regardless of if you have the patch from Apple.
1) A maintainer of an open source project you use has their GitHub account compromised due to credential stuffing and commits a malicious version.
2) You don’t pin the git clone to a particular hash or signature.
This attack is significantly more exploitable and has happened over and over again in supply chain attacks.
But look at the commonality: in both, no certificate pinning or signature checking was done. If you follow best practices, this stops both attacks dead cold.
This is the security engineering. It’s not just checking boxes. It’s evaluating risks.
> This is the security engineering. It’s not just checking boxes. It’s evaluating risks.
This is absolutely not security engineering. This is nit picking a specific attack factor and trying to argue that it’s impractical. I suspect you are wrong, but it doesn’t matter, because you are ignoring the broader class of attacks and focusing on one specific example. The class issue is that on a Mac, you cannot trust any terminal-based application to honor the CRL. This means that any site accessed from a terminal based application cannot be trusted. There are a billion ways to exploit that.
This is not good security engineering from Apple. There is no way to justify this. Humans make mistakes, and that’s just life, but we shouldn’t pretend that this is an acceptable state or an acceptable response.