Symptoms: Your system is susceptible to the Shellshock Patch, unless you have updated in the last two weeks, this is probably the case. This article applies to Linux based systems.
Solution: In Ubuntu, run sudo apt-get update, then run sudo apt-get install bash. This will update your system against the latest vulnerability.
If you are using centos, use yum.
Worse still, Rapid7’s Metasploit penetration tool , which has often been used by hackers to attack sites , now has a Shellshock module. With this and similar script-kiddie tools available, expect the number of attacks to increase dramatically because now almost no technical skill is now needed to launch an assault.