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Secretly Monopolizing the CPU Without Being Root
An anonymous reader writes "This year's
Usenix security symposium
includes a
paper
that implements a "cheat" utility, which allows any non-privileged user to
run his/her program, e.g., like so 'cheat 99% program'
thereby insuring that the programs would get 99% of the CPU
cycles, regardless of the presence of any other applications in the
system, and in some cases (like Linux), in a way that keeps the program
invisible from CPU monitoring tools (like 'top'). The utility exclusively
uses standard interfaces and can be trivially implemented by any
beginner non-privileged programmer. Recent efforts to improve the
support for multimedia applications make systems more susceptible to
the attack.
All prevalent operating systems but Mac OS X are vulnerable, though by
this kerneltrap story,
it appears that the new CFS Linux scheduler attempts to address the
problem that were raised by the paper."
I run several websites off of a single host. If I need to login to do maintenance during peak hours, I'm slowed by Apache and MySQL. This would be a nice utility if it were wrapped into SUDO.
I'd rather you do it wrong, than for me to have to do it at all.
Using up 99% of the CPU's easy!
#include
int main(int argc, char *argv[])
{
while (1) {}
return 0;
}
Summation 2
If you reply, do so only to what I explicitly wrote. If I didn't write it, don't assume or infer it.
You gun-toting marxist redneck zealot astroturfers make me sick!
My mother is a gun-toting marxist redneck zealot astroturfer, you insensitive clod!
The creator of this post (Jacob Smith) hereby releases it, and all of his other posts, into the public domain.
This is an outrage. You cannot 'sue' without lawyerd! What about the required functionality of 'sue --counter' and 'appeal'?!
The only change I can believe in is what I find in my couch cushions.
it works by avoiding running during the exact moment of a clock tick (which would be the moment when CPU usage...
--Uhm... (looks at watch...) Say, I really don't have time for wordy summaries... could you maybe cut this down into about 10 words or less? Hurry it up! I ain't got all day!
"They said I probly shouldn't fly with just one eye," "I am Bender. Please insert girder."
it run when OS not looking
Do you think this might be related to that incident where thousands of English teachers all burst into flames moments after the first SMS-enabled phone was released?