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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).

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backdoor in upstream xz/liblzma leading to ssh server compromise (www.openwall.com)

submitted 9 months ago by [email protected] to c/[email protected]

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[–] [email protected] 58 points 8 months ago (3 children)

If you're using xz version 5.6.0 or 5.6.1, please upgrade asap, especially if you're using a rolling-release distro like Arch or its derivatives. Arch has rolled out the patched version a few hours ago.

[–] [email protected] 13 points 8 months ago (1 children)

Gentoo just reverted back to the last tar signed by another author than the one seeming responsible for the backdoor. The person has been on the project for years, so one should keep up to date and possibly revert even further back than just from 5.6.*. Gentoo just reverted to 5.4.2.

[–] [email protected] 2 points 8 months ago

Just updated on void and saw the same thing

[–] [email protected] 8 points 8 months ago

Dang, Arch never sleeps, does it? That's a 24/7 incident response squad level of support.

[–] [email protected] -3 points 8 months ago (2 children)

Backdoor only gets inserted when building RPM or DEB. So while updating frequently is a good idea, it won't change anything for Arch users today.

[–] [email protected] 17 points 8 months ago (2 children)

Archlinux's XZ was compromised as well.

News post

Git change for not using tarballs from source

[–] [email protected] 13 points 8 months ago

No, read the link you posted:

Arch does not directly link openssh to liblzma, and thus this attack vector is not possible. You can confirm this by issuing the following command:
ldd "$(command -v sshd)"
However, out of an abundance of caution, we advise users to remove the malicious code from their system by upgrading either way.

[–] [email protected] 3 points 8 months ago* (last edited 8 months ago)

I think that was a precaution. The malicious build script ran during the build, but the backdoor itself was most likely not included in the resuling package as it checked for specific packaging systems.

https://www.openwall.com/lists/oss-security/2024/03/29/22

[–] [email protected] 5 points 8 months ago (3 children)

when building RPM or DEB.

Which ones? Everything I run seems to be clear.

https://access.redhat.com/security/cve/CVE-2024-3094

(and thus all the bug-for-bug clones)

[–] [email protected] 3 points 8 months ago

Those getting the most recent software versions, so nothing that should be running in a server.

[–] [email protected] 2 points 8 months ago

Fedora 41, Fedora Rawhide, Debian Sid are the currently known affected ones AFAIK.

[–] [email protected] 1 points 8 months ago

I think it needs to be

rolling release (because it was caught so quickly that it hasn't made its way into any cadence based distro yet)
using the upstream Makefile task to build a RPM or DEB (because the compromised build script directly checks for that and therefore doesn't trigger for a destdir build like Gentoo’s or Arch’s)
using the upstream provided tarball as opposed to the one GitHub provides, or a git clone (because only that contains the compromised Makefile, running autotools yourself is safe)

Points 1 and 2 mean that only rolling release RPM and DEB distros like Debian Sid and Fedora are candidates. I didn't check if they use the Makefile and the compromised tarballs.