Found a bug in Linux, a bash code injection vulnerability.

The solution to this is the update the bash package.

yum update bash  

My Question is "do I need to reboot the system"? We have 4000 servers in our environment, it will be hard to do reboot on all the systems.

  • It depends on the vulnerability. In general, you wouldn't need to reboot, but you might need to restart some services. – Gilles Aug 2 '15 at 11:49

You could simply read documentation on this vulnerability and update instructions. E.g. redhat provides extremely detailed information:

Do I need to reboot or restart services after installing the update for CVE-2014-6271 and CVE-2014-7169?

If your system uses exported Bash functions, restarting affected services is recommended. Affected interactive users may have to re-login, and screen or tmux sessions may need to be restarted.

The Bash update provided to fix these issues changes the names of exported functions in the environment. If a function is exported by the old version of Bash, it is not recognized by newly started Bash processes after the update, and essentially becomes undefined. Restarting the services ensures that the new version of Bash exports functions under the expected name, making it visible again.

To find out which services need to be restarted (or which users have to re-login), execute the following command after updating:

$ grep -l -z '[^)]=() {' /proc/[1-9]*/environ | cut -d/ -f3

The returned PIDs belong to processes which are using the old exported function definitions in their environment. These processes must be restarted. To discover which service started a certain PID and needs restarting, on Red Hat Enterprise Linux 7, use the following command:

$ systemctl status

On Red Hat Enterprise Linux 6 and earlier, use the pstree -p or ps -axuf command and look for a particular PID.

PS. If you have 4000 servers, you definitely should hire someone who can perform all the maintenance stuff. At least with such basic questions.

  • Thanks for your reply, I have someone for this activity, but just wanted double check with some of the IT Geeks. – Mongrel Aug 2 '15 at 11:31

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.