Fixed shellshock Bug in linux base system bash exploit

[Nick]

Affected distributions include:

Red Hat Enterprise Linux (versions 4 through 7)
Fedora
CentOS (versions 5 through 7)
CloudLinux
Debian


To test your system for the exploit, you can run this command from shell:

$ env x='() { :;}; echo vulnerable' bash -c "echo this is a test"
vulnerable
this is a test

Most linux distributions have issued a fix, and for Redhat, CloudLinux and CentOS systems you can run yum update which will bring down the updated version of Bash.

yum update bash

Your system is no longer vulnerable if the above test returns this:

$ env x='() { :;}; echo vulnerable' bash -c "echo this is a test"
bash: warning: x: ignoring function definition attempt
bash: error importing function definition for `x'
this is a test

refer: http://ventraip.com.au/blog/announcements/bug-in-linux-bash-causes-shellshock-update-required/