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As I can find in Mac OS X

smarek:~ marekseberaold$ dmesg
Unable to obtain kernel buffer: Operation not permitted
usage: sudo dmesg

Is this really important, to disable access to dmesg output for non-root / non-administrative users? Why is Apple doing this at all?

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Apparently, the need to run as root comes from the original BSD command. I think that modern FreeBSD has abandoned the need for root dmesg. –  new123456 Jan 26 '12 at 12:15

1 Answer 1

A clear "yes" from my side:

An attacker can use it to snoop kernel messages, e.g. about segfaults, kernel errors and thus use it as feedback loop for exploit optimization. Another usecase: the iptables LOG target will write to same buffer, information about connections of other users can then be misused to spoof packets with better chance for success.

I guess someone skilled will find even more ways to use dmesg to aid in privilege escalation.

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