In 2025, I found and disclosed a bunch of vulnerabilities in GPG, the most used PGP implementation, and held a talk at 39c3 about it. **S...
  • GalacticGrapefruit@lemmy.world
    0·
    1 个月前

    Wearing a dog collar for a highly technical live presentation of a critical security feature requires a degree of personal confidence I can only admire.

  • ChunderBustickles@piefed.nzEnglish
    0·
    1 个月前

    Please bear with my dumb ass. if validating a certificate / signature is risking an RCE, does that essentially make this a planet-wide potential supply chain hack (wherever gnupg is used, at least?)

  • modem_down@thebrainbin.orgOP
    0·
    1 个月前

    I’m probably having a brainfart (watched the video during insomnia), but re: the section 12m 10s into the video, can someone please clarify why “the instructions are dangerously wrong”?

    I understand it relates to the earlier demo in which those instructions gave the illusion of “verifying” an ISO that was in fact malicious. But:

    • why did those instructions fail to genuinely verify the ISO?
    • what would the correct instructions have been?
    • tribut@infosec.pub
      0·
      1 个月前

      Cleatext signing (having the signature and data in the same file) is broken in many ways. It is possible to put unsigned data at the top of the file in a way that sha256sum will use it. Watch the 39c3 GPG talk if your interested in the gory details.

      The solution is to use detached signatures (checksum.txt and checksum.txt.gpg to verify that). This makes sure that all of checksum.txt is actually covered by the signature.

      • Walters, Fern@bookwyr.meEnglish
        0·
        1 个月前

        cc @[email protected]
        or, binary signatures, [which I prefer: compressionable], as textfiles are insecure formats.

        I prefer a headed, mided, and tailed verification, similar to MPEG keyframing, for constant stream verification.

        • lurch (he/him)@sh.itjust.works
          0·
          1 个月前

          idk about the specific formats, but i don’t think you can say that in general. what are those two formats and why does it make a difference in this case?

          • Walters, Fern@bookwyr.meEnglish
            0·
            1 个月前
            1. what binary signatures offer:
            • smaller sizes
            • ability to compression
            • the actually signature
            • confidentiality

            1. File headersdef, midingdef, tailingdef.

            2. why textfiles are insecure

            i don’t think you can say that in general

            What is your academic literacy please?

            Cite your papers please.

            or gen z:
            Drop your academic flex.
            What grade you at?
            papers pls🙏

            orly

            • lurch (he/him)@sh.itjust.works
              0·
              1 个月前

              no, i mean, you say text files are insecure and you prefer binary.

              while it is true that processing text files needs additional code (validating/converting charsets/encoding), which increases the number of potential attack vectors, security threats introduced by this are not a fault of them being text, but of the parser code.

              at the end of the day the attacker just switches from text editor to hex editor to prepare a malicious file.

              • Walters, Fern@bookwyr.meEnglish
                0·
                1 个月前

                I was never talking about vectorization, but regular file integrity. Textfiles have no error correctiveness. Yet a binary can be. Either can be edited and vectorized. Heck the point of this talk is manipulating expectations, as sha256sum isn’t file verifier.