[Fix] Linux Bash Code Injection Vulnerability – ShellShock

ShellShock is new Linux vulnerability affecting all versions of Bash package. This vulnerability is worse than HeartBleed! This command line vulnerability is present in Mac OS X too. Basically it’s there in all the systems having Bash, a software used to control the command line in Unix.

To test if you are vulnerable to ShellShock, run this command:

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

If you see output:

vulnerable

this is a test

that means you are vulnerable!

Fix for Redhat packages:

yum update bash

Fix for Ubuntu/Debian packages:

apt-get upgrade bash

After running above commands, check again to see if you are vulnerable:

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

If you see below output, that means you are no longer vulnerable

bash: warning: x: ignoring function definition attempt

bash: error importing function definition for `x'

this is a test