Comment by krunck
17 hours ago
Wow. I tried it on an old testing VM of Ubuntu 24.04 that had not been touched for a few months. Instant root with the bonus that any user that runs "su" gets root too. I updated the VM thinking it would be fixed afterward. Nope.
You’d have to reinstall the su binary itself I guess
It just changes the page cache for the su binary, a reboot will revert it.
No need to reboot:
sync && echo 3 >/proc/sys/vm/drop_caches