The interwebz is abuzz with the latest vulnerability for *nix based systems that us the BASH shell. The so-called Shell Shock exploit allows devious users to run commands against your system using a bug in the way BASH handles environment variables. Ouch. To check if your system is vulnerable run the following in a shell:

env x='() { :;}; echo vulnerable’ bash -c “echo this is a test”

If your system is vulnerable you’re going to see this:

vulnerable
 this is a test

If your system is not vulnerable you’re going to see something like this:

bash: warning: x: ignoring function definition attempt
bash: error importing function definition for `x'
this is a test

There’s a patch available for Ubuntu systems already. All I did was this:

sudo apt-get update
sudo apt-get install bash

And hey presto the system is no longer vulnerable.