Check the version of bash
Please Install the Updated Packages.
Michal Zalewski discovered that Bash incorrectly handled parsing certain function definitions. If an attacker were able to create an environment variable containing a function definition with a very specific name, these issues could possibly be used to bypass certain environment restrictions and execute arbitrary code. (CVE-2014-6277, CVE-2014-6278) Please note that the previous Bash security update, USN-2364-1, includes a hardening measure that prevents these issues from being used in a Shellshock attack.
bash on Ubuntu 14.04 LTS , Ubuntu 12.04 LTS , Ubuntu 10.04 LTS
Get the installed version with the help of detect NVT and check if the version is vulnerable or not.