When the xz backdoor was discovered, I quickly uninstalled my Arch based setup with an infected version of the software and switched to a distro that shipped an older version (5.5 or 5.4 or something). I found an article which said that in 5.6.1-3 the backdoor was “fixed” by just not letting the malware part communicating with the vulnerable ssh related stuff and the actual malware is still there? (I didn’t understand 80% of the technical terms and abbreviations in it ok?) Like it still sounds kinda dangerous to me, especially since many experts say that we don’t know the other ways this malware can use (except for the ssh supply chain) yet. Is it true? Should I stick with the new distro for now or can I absolutely safely switch back and finally say that I use Arch btw again?

P. S. I do know that nothing is completely safe. Here I’m asking just about xz and libxzlk or whatever the name of that library is

EDIT: 69 upvotes. Nice

  • rtxn@lemmy.world
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    5 months ago

    TL;DR: starting with 5.6.1-2, XZ is safe on Arch. Safe as in not affected by this particular vulnerability.

    Look here: https://gitlab.archlinux.org/archlinux/packaging/packages/xz/-/commit/881385757abdc39d3cfea1c3e34ec09f637424ad

    And here: https://security.archlinux.org/ASA-202403-1

    5.6.1-2 is where the package switched from building from the tarball (backdoored) to the upstream git repo (clean). The tarball release contained some extra build instructions (which didn’t exist in the git repo) that added the backdoor during the build process. The issue arose from the downstream maintainers’ assumption that the contents of the tarball and the git repo were identical.

    Subsequent changes, and 5.6.1-3, were mostly administrative, like changing the git repository’s URL (since the maintainer’s github account was banned) and locking out Jia Tan’s PGP key.

    an article which said that in 5.6.1-3 the backdoor was “fixed” by just not letting the malware part communicating with the vulnerable ssh related stuff

    That article is bullshit, don’t believe a thing it says. Arch was not affected by the SSH vulnerability because the sshd binary did not link liblzma where the backdoor existed, so they could never communicate in a way that could be exploited by this particular vulnerability. It was not part of the fix.

    • GolfNovemberUniform@lemmy.mlOP
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      5 months ago

      5.6.1-2 is where the package switched from building from the tarball (backdoored) to the upstream git repo (clean)

      This is what I was looking for. Though if 5.6.1-2 doesn’t contain the backdoor, why is it listed as the last version that does contain it everywhere?

      • rtxn@lemmy.world
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        5 months ago

        why is it listed as the last version that does contain it everywhere?

        I don’t know, but the official advisory is most likely to be correct. Everything else is a game of Chinese whispers where the information becomes less reliable the more it is passed on. Maybe it’s because -2 still had Jia Tan’s signing key, and could have, theoretically, accepted commits signed by them.

        Where is it listed as such? Can you give examples?

        • GolfNovemberUniform@lemmy.mlOP
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          5 months ago

          Hmm I looked it up and I’m either searching it wrong or it seems like the articles were edited and the stuff about 5.6.1-2 being infected is deleted. I think you’re right about the keys. That could be the reason for yellow press to exaggerate the problem

  • unreliable@discuss.tchncs.de
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    5 months ago

    The back door was crafted to be used by a very specific encryption key. You are are vulnerable if the attackers are specifically targeting you. If you are a tangent of a nation, you should be worried:)

    • GolfNovemberUniform@lemmy.mlOP
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      5 months ago

      Well idk what “a tangent of a nation” means but I have political opinions very different to what my nation wants me to have so it might actually be a problem for me

      • 520@kbin.social
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        5 months ago

        What they mean is if you are a affiliated with a national government. You might also be a target if you are very very rich.

        If you’re an average Joe, they probably won’t burn it on you.

        • The Doctor@beehaw.org
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          5 months ago

          It’s already burned by being discovered.

          And, never underestimate the utility of a large botnet.

        • ahal@lemmy.ca
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          5 months ago

          He could be an average Joe who works in the IT department of a company a national government would be interested in.

      • unreliable@discuss.tchncs.de
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        5 months ago

        I mean, appears a country is responsible for the attack after 2 years of preparation. If they don’t like you, probably was easy to send someone knock your door instead. Relax :)

  • Titou@feddit.de
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    5 months ago

    When i first heard of xz backdoor, i updated my arch system and the xz-utils package to 5.6.1-3 which in the version numbers seems to be a patch, and it seems to be, so think you’re safe from now

  • Quill0@lemmy.digitalfall.net
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    5 months ago

    Do you host anything on your network to tne internet that allows anyone ssh access to your computers? More simply do you have port 22 open on your router or firewall? If you don’t or said no, then don’t worry about it.

    • GolfNovemberUniform@lemmy.mlOP
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      5 months ago

      ssh was installed because it’s needed by one of the GNOME’s components (the keyring I think). ssdh was disabled the last time I looked at it though. But my router highly unfortunately uses stock proprietary firmware because I couldn’t get OpenWRT working on it. That thing can have all the ports opened lol