$ env x='() { :;}; echo vulnerable' /bin/sh -c "echo this is a test"
vulnerable
this is a test
$ curl -O http://supportdownload.apple.com/download.info.apple.com/Apple_Support_Area/Apple_Software_Updates/Mac_OS_X/downloads/031-08421.20140929.4Syvs/BashUpdateMavericks.dmg 2> /dev/null
$ hdiutil attach -quiet BashUpdateMavericks.dmg
$ sudo installer -pkg /Volumes/OS\ X\ bash\ update/BashUpdateMavericks.pkg -target LocalSystem
installer: Package name is Actualización de Bash para OS X
installer: Installing at base path /
installer: The install was successful.
$ env x='() { :;}; echo vulnerable' /bin/sh -c "echo this is a test"
this is a test
$ hdiutil detach -quiet /Volumes/OS\ X\ bash\ update |