Bad title. This is CVE-2024-3094. Run “xz --version” to see if you are affected.
Running Ubuntu 23.10 with xz-utils 5.41 which is unaffected. Versions 5.6.0 and 5.6.1 are the malicious packages. I used Synaptic Package Manager to search for it.
The bad actor had a launchpad bug to pull it into the Ubuntu LTS beta. Serious kudos to the person who discovered it, literally in the nick of time.
Using the F40 preview with KDE and a regular update from Discover rolled xz back to the known good version 5.4.6
I’m on Void, and I had the malicious version installed. Updating the system downgraded xz to 5.4.6, so it seems they are on it. I’ll be watching discussions to decide if my system might still be compromised.
some people in my mastodon feed are suggesting that the backdoor might have connected out to malicious infrastructure or substituted its own SSH host keys, but I can’t find any clear confirmation. More info as the investigation progresses.
I guess at this point if you’re on Fedora 40 or rawhide clear / regen your host keys, even after xz version rollback
or substituted its own SSH host keys,
why would the backdoor do that? It would immediately expose itself because every ssh client on the planet warns about changed host keys when connecting.
Perhaps it was a poorly worded way of suggesting that invalidating host keys would invalidate all client keys it could potentially generate? Either way it’s a lot of speculation.
Resetting the keys and SSH config on any potentially compromised host is probably not a terrible idea
Nuke from orbit might be an overreaction, if you need that machine perhaps disable ssh or turn the machine off until later next week when the postmortems happen. If you need that trusted machine now, then yes fresh install
Honestly doing a fresh install is a good test of your recovery abilities. You should always have a way to restore critical content in an emergency
