From Wikipedia, the free encyclopedia
Linux is a family of open source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991 by Linus Torvalds. Linux is typically packaged in a Linux distribution (or distro for short).
Distributions include the Linux kernel and supporting system software and libraries, many of which are provided by the GNU Project. Many Linux distributions use the word "Linux" in their name, but the Free Software Foundation uses the name GNU/Linux to emphasize the importance of GNU software, causing some controversy.
Community icon by Alpár-Etele Méder, licensed under CC BY 3.0
Arch wasn't affected at all, cause the backdoor trigger was only on deb and rpm distros.
However it still a good practice to update your system and leave this version behind. Anyway, Arch already updated and is no longer distributing the backdoor version, therefore 5.6.1-3 is safe
You can use Arch btw again. Actually, you never had to leave it at first
To add to your point: The .deb ones are most likely safe, since it would only be on the unstable & experimental branches. Your garden variety production servers & personal computers should be fine. That is unless you're into some unusual setup like with playing around with the upcoming version, or for some reason are pulling your own xz build.
Can't speak for the .rpm tho.
Fedora 39 and 40 (which is still in beta) uses xz 5.4. Fedora 41/rawhide (essentially the development branch) was affected it seems: https://access.redhat.com/security/cve/CVE-2024-3094. CentOS Stream and RHEL have way more outdated packages than that, so they were never vulnerable to this backdoor.
openSUSE Tumbleweed (their rolling release) was affected: https://news.opensuse.org/2024/03/29/xz-backdoor/, Enterprise or Leap were unaffected.
Ah, so the .rpm is pretty much like the .deb in that it's mostly unaffected. Speaking of, I think the .deb side may have VanillaOS affected since it's based on Debian's unstable branch.
Yeah, I checked myself when this was first a thing. Debian 12 and Ubuntu 22.04 latest are on 5.4 and 5.2 respectively.
Yeah, all the current LTSes should be safe. Not sure about the Ubuntu 23.10, but the next LTS (24.04) is confirmed to be affected, hence the delay.
Not quite. It wasn't confirmed to be affected, but they can't prove that the build environment itself wasn't compromised, thus the rebuild.
As a result of CVE-2024-3094 332, Canonical made the decision to remove and rebuild all binary packages that had been built for Noble Numbat after the CVE-2024-3094 332 code was committed to xz-utils (February 26th), on newly provisioned build environments. This provides us with confidence that no binary in our builds could have been affected by this emerging threat.
https://discourse.ubuntu.com/t/noble-numbat-beta-delayed-xz-liblzma-security-update/43827
And in the follow-up:
Was the vulnerable library ever in the Ubuntu 24.04 LTS (Noble Numbat) daily builds?
No.
https://discourse.ubuntu.com/t/xz-liblzma-security-update-post-2/43801
Thanks for the correction!
"Safe" is a strong word to use. It's safe from that specific backdoor, and it seems like the known backdoor was the main goal of the attackers, but we don't know if they're playing 4D-Chess and have already implemented another backdoor which they're actively using.
I see what you did there.
What I did there? o.O
I don't even know
Oh, I thought the "You can use Arch btw again." is a play on the "I use Arch, BTW."-meme. :D It's even better, because this was not intentional I guess.
Ah! Okay...
Well, it was intentionally xD
But I didn't thought it would be a funny pun hahaha
Anyway, I did it mostly because the OP also did
I see. But yours was a little bit more sneaky. And I loved it.
You switched distros because of this? 😆
Yes
Well, live and learn :)
TL;DR: starting with 5.6.1-2, XZ is safe on Arch. Safe as in not affected by this particular vulnerability.
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.
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?
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?
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
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:)
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
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.
It's already burned by being discovered.
And, never underestimate the utility of a large botnet.
He could be an average Joe who works in the IT department of a company a national government would be interested in.
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
It's over. Nothing to see here. Move along.
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.
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