Important APT security update - please read the instructions to upgrade APT safely https://www.debian.org/security/2019/dsa-4371
@debian Ouch. I wondered why Debian wasn't using HTTPS. Any plans to do so now, in the light of this vulnerability?
@wizzwizz4 Debian already supports https. But TLS certificates depends on CAs, and most on them aren't trustworthy. Unless you use DANE/HPKP, don't expect https to *prevent* MITM attacks.
@devnull Fair point. However, loads of CAs are trusted by default for _everything else_, and it's better to pile on extra layers so an attacker will need to break _all_ of them.
@wizzwizz4 That's a huge problem. CAs shouldn't be trusted, because they don't give a crap about security. They're only for profit.
More software need to support DANE, more admins need to learn how to configure DANE and HPKP properly.
1. Let's Encrypt.
2. It helps to prevent attackers from easily utilising a vulnerability in one layer of mitigation.
Yeah, it's not perfect. But yes, it's better than nothing. HTTPS + DANE is better than HTTPS + CAs, but HTTPS + DANE + CAs is even better. And @debian doesn't have DANE yet, anyway!
Oh, I see what you're saying. Debian is the CA, and bundles its own signature with Debian? Ehh… not sure how much security nuts would appreciate that. I certainly wouldn't appreciate the software distributor having the technical means to transparently intercept all of my traffic. But it's certainly a possible solution.
@wizzwizz4 > It doesn't promise that the certificate is actually Debian's certificate
CAs don't, they deliver forged certs to malicious third parties, either for profit (see what micro$oft did with ie certificates in Tunisia (and NOT only in Tunisia) years ago, with the help from malicious CA, to help the government to spy on people), or by mistake (even Let's Encrypt has been abused)
HPKP does, a certificate can't be valid if it hasn't been signed by the pinned keys.
@wizzwizz4 Not the same goal. DANE have a mode to verify sefl-signed certificate which makes CA obsoletes. If Debian is it's own CA, DANE wouldn't be necessary but it's a plus, as DANE can be used with a CA as well.
HPKP is to say "The certificate is only if it has been signed the this/these key(s)".
Let's say Debian has a CA for apt, If your goal is to check if apt repos cert have been signed by debian's CA and not by a malicious CA, checking the signing key is a good option.
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