Linux Security Exploit (Iglulik was attacked)

Warning!!!! This security exploit has not been widely published but it IS actively being exploited. Someone caused my server that houses our customers /home directories to spontaneously reboot trying to exploit it. Fortunately the kernel logged their attempts. See: In our cause I performed measurements on system load, web page loading times and latency with and without this CPU feature turned off and in our case it made no measurable difference so I turned it off with: echo ‘off’ > /sys/devices/system/cpu/smt/control. I put this in /etc/rc.local which is enabled on our machines for this and some other adjustments.