I thought Arch was the only rolling distro that doesn’t have the backdoor. Its sshd is not linked with liblzma, and even if it were, they compile xz directly from git so they wouldn’t have gotten the backdoor anyway.
liblzma is the problem. sshd is just the first thing they found that it is attacking. liblzma is used by firefox and many other critical packages.
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)"
Yes, this sshd attack vector isn’t possible. However, they haven’t decomposed the exploit and we don’t know the extent of the attack. The reporter of the issue just scratched the surface. If you are using Arch, you should run pacman right now to downgrade.
Interestingly, looking at Gentoo’s package, they have both the github and tukaani.org URLs listed:
https://github.com/gentoo/gentoo/blob/master/app-arch/xz-utils/xz-utils-5.6.1.ebuild#L28
From what I understand, those wouldn’t be the same tarball, and might have thrown an error.
