systemd-machined: unprivileged users can terminate arbitrary processes
When systemd-machined >= v259 (or v258 with a custom `polkit` policy that allows `register-machine` access) is running on a desktop system, an unprivileged user logged in a desktop graphical session can kill arbitrary processes, even privileged ones.
- versions older than v259 are not affected, unless unprivileged access is granted for the `register-machine` polkit action via a local, custom policy config file
- versions older than v258 are not affected
- unrelated to the systemd service manager (pid 1 or user session managers)
- systemd-machined is not typically installed by default, and is typically in an optional, separate package (e.g.:
In systemd 259, systemd-journald can send ANSI escape sequences to the terminals of arbitrary users when a "logger -p emerg" command is executed, if ForwardToWall=yes is set.