As you may have already heard, Bash (the popular Linux and Unix shell) has a serious security problem that can cause trouble to your server(s) and any other Linux devices that you are using. According to Red Hat researchers, the severity of the bug can be classified as "catastrophic”. This is due to the fact that there are many possible ways to call Bash by an application. So this may allow attackers to upload files, execute commands, send spam and more.
There is an easy way to find out whether your system is vulnerable. You can simply check your system from a command line by typing:
env x='() { :;}; echo vulnerable' bash -c "echo this is a test"
If the system is vulnerable, the output will be:
vulnerable this is a test
If you run the above example with the patched version of Bash, you should get an output similar to:
$ 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
