Fix remote exploit vulnerability in bash
An attacker could inject and subsequently execute arbitrary shell commands in applications or services that call bash. The major attack vectors that have been identified in this case are HTTP requests and CGI scripts. Certain services and applications allow remote unauthenticated attackers to provide environment variables, allowing them to exploit this issue.
How to Fix
To test if your version of Bash is vulnerable to this issue, run the following command:
If the output of the above command looks as follows:
this is a test
That means you are using a vulnerable version of Bash. The patch used to fix this issue ensures that no code is allowed after the end of a Bash function.
Thus, if you run the above example with the patched version of Bash, you should get an output similar to:
bash: warning: x: ignoring function definition attempt
bash: error importing function definition for `x'
this is a test
Fix this bug now :
$ apt-get --only-upgrade install bash
You should check once again to make sure everything is ok :))