As you may already know, from the last days a bash vulnerability is started being exploited. All majority of distros ( Redhat / Centos, Debian, Ubuntu) already launched a fix for this, so all you need to do is to update your linux server:
for Redhat / Centos servers : yum update
for Ubuntu and Debian : sudo apt-get update
Please do it as soon as possible , because it is the biggest threat ever !
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