Thread

1. kpcyrd · 1790876562 · focus · HN ↗

   This article is full of mistakes and misleading claims:

   1) It's claiming SHA1 insecurity is theoretical, while SHAttered from 2017 was specifically a pratical proof of concept. The only reason Git wasn't affected, is because they didn't bother bruteforcing a git-blob prefix.

   2) It's claiming collision attacks don't matter, only second-preimage attacks do. This is incorrect, collision attacks are enough for code-smuggling problems, when two repositories are on the same git commit (verified by the full commit hash), yet contain different code in their git checkout.

   3) The Linus quote "The real security is in distribution" is arguing that "git's content-addressed system should not be used to address content". It's arguing that, in case of curl|sh, you shouldn't use a sha256sum-gate to pin the content to something you've reviewed, you should instead ensure curl is fetching from an https server.

   1. schacon · 1790877053 · focus · HN ↗

      1) I link to the SHAttered paper, as well as Shambles. Git projects were not affected because it is an inefficient attack vector. I say it's impractical to exploit, which I think everyone agrees with.

      2) I specifically argue that even if both attacks were practical and cheap, it's still not the problem we should be focusing on.

      3) Have you read this email (that I linked to)? It is almost the same general message (20 years ago) that this blog post is. It literally goes though a theoretical object replacement attack and how dumb this scenario is and so SHA-1 is fine.

      <a href="https:&#x2F;&#x2F;lore.kernel.org&#x2F;git&#x2F;Pine.LNX.4.58.0504291221250.18901@ppc970.osdl.org&#x2F;" rel="nofollow">https:&#x2F;&#x2F;lore.kernel.org&#x2F;git&#x2F;Pine.LNX.4.58.0504291221250.1890...

      1. bityard · 1790909767 · focus · HN ↗

         In agreement that this is good old fashioned cargo-cult security theatre, but tom7 also coined a more catchy phrase for this, he calls it &quot;toxic max-security.&quot; <a href="http:&#x2F;&#x2F;tom7.org&#x2F;httpv&#x2F;httpv.pdf" rel="nofollow">http:&#x2F;&#x2F;tom7.org&#x2F;httpv&#x2F;httpv.pdf

         1. ozim · 1790922095 · focus · HN ↗

            Oh I call those people „TLS antivaxxers”.

            Conveniently Tom didn’t mention anything about Edward Snowden and what he published. That was basically start of TLS everywhere.

            Then he didn’t mention ISP idiots that were actually injecting ads to cute websites like Tom’s. I hope Tom likes when his website is used by ISP to make money on ads he doesn’t have any control over.

            Then he goes on to criticize certificate transparency, but it works. Companies got kicked out from trusted root program because they were doing stupid stuff like making certs they shouldn’t.

            Let’s not forget glorious state of Kazakhstan where without TLS they would just listen to all traffic - well with TLS they were trying to pull MITM but were uncovered and got their stuff removed by TLS ecosystem.

            1. ForHackernews · 1790937960 · focus · HN ↗

               &gt; I hope Tom likes when his website is used by ISP to make money on ads he doesn’t have any control over.

               You mean like how Google makes money showing ads against your content that you don&#x27;t control? You mean how basically every ad network works?

               1. ozim · 1790952446 · focus · HN ↗

                  What ISPs were doing they were injecting ads and you had no way of knowing it happens unless some visitor was annoyed enough to make you aware by sending you a screenshot.

                  With Google you have to make an agreement and put piece of code in your website willingly and then you get minimal cut but still, that is totally your choice.

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