Related discussion:
https://news.ycombinator.com/item?id=39865810
https://news.ycombinator.com/item?id=39877267
Advisories:
Man, there is a lot of concerning stuff there.
In particular, one person commented that the original xz maintainer was possibly subjected to a pressure campaign to hand over maintainership.
Another interesting data point: about 2 years ago there was a clear pressure campaign to name a new maintainer:
https://www.mail-archive.com/xz-devel@tukaani.org/msg00566.html
At the time I thought it was just rude, but maybe this is when it all started.
I don’t know how many open-source project maintainers would be on guard for something that subtle, people coordinating to take over maintainership of a project.
I mean, xz isn’t normally something you’d immediately think of as security-critical. I doubt that a maintainer knows or thinks about about all the potential downstream dependencies (in this case, not even a standard sshd depedendency, but one that came up because of a patch that Debian used to add some systemd functionality).
EDIT:
I mean, xz isn’t normally something you’d immediately think of as security-critical.
On second thought, it actually is, given that Debian packages are xz-compressed.
Wow… Luckly I don’t use systemd which seems to be the vector causing the sshd backdoor, via liblzma…
Pretty scary anyway.
I bet that you use software packages that are built and authored on systems that have systemd+sshd, though.
What happens if development or build machines belong to people who control projects that you trust and have been compromised?
Do you use a web browser? Do you use a graphical desktop environment? Are the machines those guys use vulnerable? Are the developers of the libraries that they depend on vulnerable?
Remember, this guy was attacking a downstream project (sshd) by compromising and signing source in a specific tarball of a library – the malicious code never made it into git – used by an unrelated piece of software (systemd) that some distros, not even the ssh guys, happened to link into sshd’s memory space. He’s trying to compromise unrelated software via elaborate supply chain attacks.
