How often are people “git clone”ing a repo without browsing to the GitHub site first? Safari would throw up certificate errors. And also, TLS on Git doesn’t even authenticate the code you’re downloading is legitimate at all. It could be modified by the Git host or a supply chain attack, etc.
Yea, it’s not great. Ideally the risk is reduced to zero from patching. But a lot of the times we accept some level of cybersecurity risk out of practicality. This is why we have responsible disclosure windows lasting months. It takes a while to do proper release engineering and testing for something like a whole OS update.
[–] dannyw 1 day ago
[–] invokestatic 1 day ago
To know whether a request is a git client or web browser, an attacker needs to be able to inspect the contents of the web request (to check the user agent or whatever). If the site is using a legitimate certificate, the attacker has no way to inspect the contents because it is encrypted with a key they do not control.
If an attacker used their own, eMudhra-signed certificate, it would throw the certificate error in Safari.
[–] dannyw 1 day ago
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.
[–] invokestatic 1 day ago
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.
[–] dpark 1 day ago
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.
[–] paimapi 1 day ago
1) Why wouldn't you have a SSOT for certs and instead rely on patching different apps individually?
2) Doesn't this violate defense in depth? Exploits for a widely disclosed issue now have turnaround activation within hours, not weeks. Not patching all surface areas and actively disclosing as such seems very much like drawing up a map for a jailbroken LLM to gin up a rudimentary attack.
3) Also doesn't this violate the principle of secure by default especially for power users who are more likely to be the ones with higher privileges across distributed systems?
[–] dualvariable 1 day ago
Browsers came along and they wanted to maintain their own cert store because operating system flat files were often out of date.
Operating systems grew their own stores because they wanted some kind of registry that was more integrated with the rest of their ecosystem.
Nobody coordinated. CLI tools and unix libraries don't care about browsers or O/S registries, operating systems have requirements so that they can't use the flat files, everyone screams about stuff like systemd turning unix into windows.
And it will continue to proliferate. System management tools often ship their own certs since the O/S certs can be out of date and untrustworthy and may not be able to talk to AWS before you bootstrap the management tool and update the system certs because people still run ancient shit like RHEL5. This is more or less the same reason browsers ship their own as well. I've made the decision to ship an embedded cert store in a product before, and nothing has fundamentally changed that would cause me to rethink that decision (even though for people who have an up-to-date O/S it is strictly additional cost that they now have to track a cert store in another product--but you have to build for the lowest common denominator).
[–] invokestatic 1 day ago
2) Yes, but actually, this is exactly why we have defense in depth. This is a temporary measure while a permanent patch is coming. Defense in depth means a single hole does not result in compromise. I would argue that this situation with Apple demonstrates defense in depth actually working as intended. If this was the permanent solution, and no further patch was coming from Apple, then yes, it would violate defense in depth.
3) Related to above, yes. But it’s not permanent.
One of the certificates literally has a private key of 4; it's as compromised as it could quite possibly be. This is not a "one of the intermediates have a weak and possibly crackable key" or "a bunch of incorrect certs were issued but the issuance was patched".
To a MITM attacker, git clones can be easily distinguished from visiting in Safari. You could choose to only poison git clones; without poisoning anything else.
Heck, you can probably build an exploit kit in a hour; camp out around a Starbucks or McDonalds with open wifi, and start compromising git clones and deliver malicious payloads.