Reading secret data out of kernel memory is very bad on cloud environments. Keep in mind that the kernel deals with a lot of cryptography.
sudo cat /dev/mem
I'm having a hard time understanding why this is worse than any other local root escalation bug except for the consequences of the necessary patch.
EDIT: I see that /dev/mem is no longer a window on all of physical RAM in a default secure configuration. Is it true that there's no way for root to read kernel memory in a typical Linux instance? If so, the severity of this issue makes more sense to me.
> I'm having a hard time understanding why this is worse than any other local root escalation bug except for the consequences of the necessary patch.
It's not, as far as I'm aware. The fact that the patch has perf consequences is why it's such a big deal.
a) It would allow any non-root process to read full memory, including the kernel and other processes, or
b) It would allow one cloud VM to read full memory of other cloud VMs on the same physical machine, or
c) With enough cleverness, it would allow even sandboxed Javascript on a web page to read full memory of the computer that it is running on.