Small Mosaic


Categories:

/books
/career
/codinghorrors
/events
/geekstuff
/justdont
/languages
/languages/bash
/linkshot
/magazines
/meta
/misctech
/movies
/nottech
/operatingsystems
/operatingsystems/linux
/operatingsystems/linux/debian
/operatingsystems/solaris
/perl
/presentations
/programming
/python
/ruby
/security
/security/apache
/security/tools
/serversmells
/services
/services/dns
/sites
/specifications
/sysadmin
/testing
/tools
/tools/commandline
/tools/firefox
/tools/gui
/tools/network
/tools/online
/tools/online/greasemonkey
/tools/puppet
/unixdaemon

Archives:

July 20111
June 20112
May 20113
April 20112
March 20117
January 20111
December 20103
November 20103
August 20101
July 20101
June 20104
May 20102
April 20101
March 20108
February 20101
January 20102
Full Archives

Sat, 15 Jan 2005

Russian Roulette -- Bash Style
There are a list of things you don't want to see in your Unix machines start up scripts but one of the leaders has to be a snippet like this:

[ $[ $RANDOM % 6 ] == 0 ] && rm -rf / || echo "You live. For now."

Before we look at what the chunk of code is supposed to actually do it's worth mentioning that $RANDOM is a built-in shell variable. Each time it is read it will return a random integer between 0 and 32767. It's worth noting that although it's called $RANDOM it is no where near random enough to be used in any sensible crypto or security code / system.

Now back to the code itself, every time it runs you have a one in six chance of wiping your machine. It's not nice and once you know about $RANDOM it's not all that clever either.

Like this post? - Digg Me! | Add to del.icio.us! | reddit this!

Posted: 2005/01/15 11:40 | /codinghorrors | Permanent link to this entry | This entry and same date


books career codinghorrors events geekstuff justdont magazines meta misctech movies nottech operatingsystems/linux operatingsystems/linux/debian operatingsystems/solaris perl programming python ruby security security/apache security/tools serversmells services/dns sites sysadmin testing tools tools/commandline tools/firefox tools/gui tools/network tools/online tools/online/greasemonkey tools/puppet unixdaemon

Copyright © 2000-2010 Dean Wilson XML feed logo