How To Patch and Protect Linux Server Against the Glibc GHOST Vulnerability # CVE-2015-0235

The GHOST (CVE-2015-0235) vulnerability is a serious vulnerability that affects the glibc library, which is a core part of the Linux operating system. This vulnerability allows an attacker to execute arbitrary code with the permissions of the user running the affected software, potentially allowing the attacker to take control of the system.

To patch and protect a Linux server from the GHOST vulnerability, you will need to update the glibc library to a version that includes the fix for this vulnerability. The specific steps to do this will depend on the Linux distribution you are using.

Here are some general steps you can follow to patch and protect a Linux server from the GHOST vulnerability:

1. Check the version of the glibc library currently installed on your system. You can do this by running the following command:

ldd --version

This will display the version of the glibc library installed on your system.

2. Determine if your system is vulnerable to the GHOST vulnerability. You can do this by running the GHOST.c test program provided by Red Hat. This program is designed to test if a system is vulnerable to the GHOST vulnerability by attempting to exploit it. You can download and compile the GHOST.c test program by running the following commands:

wget https://www.qualys.com/apps/pdf/GHOST.c
gcc GHOST.c -o GHOST

To test if your system is vulnerable, simply run the GHOST program:

./GHOST

If your system is vulnerable, the GHOST program will display a message indicating that the vulnerability has been successfully exploited. If your system is not vulnerable, the GHOST program will exit without displaying any message.

3. Update the glibc library to a version that includes the fix for the GHOST vulnerability. The specific steps to do this will depend on the Linux distribution you are using. Here are some general steps you can follow:

• For CentOS and Red Hat Enterprise Linux:

yum update glibc

• For Debian and Ubuntu:

apt-get update
apt-get upgrade libc6

• For Fedora:

dnf update glibc

4. Reboot the system to complete the update process.

It is important to note that these steps may vary depending on the specific Linux distribution and version you are using. You may need to consult the documentation for your specific distribution for more detailed instructions.

It is also important to keep your system up to date with the latest security patches and updates to protect against vulnerabilities like the GHOST vulnerability. You should regularly check for and apply updates to ensure that your system is secure.