How to Manually Remove the cPanel-Provided Hardened Kernel

Overview

This document describes how to manually replace the cPanel-provided hardened kernel with a standard kernel.

Remove the kernel

To manually replace the cPanel-provided hardened kernel with a standard kernel, perform the following steps:

1. Log in to your server via SSH.
2. Run the following commands:

   1 2	rm /etc/yum.repos.d/cPkernel.repo yum list --showduplicates kernel

   The system will return a list of available kernels that you can install.

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   [root@c6 ~]# yum list --showduplicates kernel Loaded plugins: fastestmirror Loading mirror speeds from cached hostfile * base: reflector.westga.edu * epel: mirror.compevo.com * extras: ftp.osuosl.org * updates: dallas.tx.mirror.xygenhosting.com Installed Packages kernel.x86_64 2.6.32-573.26.1.el6 @updates/6.7 kernel.x86_64 2.6.32-642.1.1.el6 @updates kernel.x86_64 2.6.32-696.299.10.3.cp6 @cPkernel Available Packages kernel.x86_64 2.6.32-696.el6 base kernel.x86_64 2.6.32-696.1.1.el6 updates kernel.x86_64 2.6.32-696.3.1.el6 updates kernel.x86_64 2.6.32-696.3.2.el6 updates kernel.x86_64 2.6.32-696.6.3.el6 updates kernel.x86_64 2.6.32-696.10.1.el6 updates kernel.x86_64 2.6.32-696.10.2.el6 updates kernel.x86_64 2.6.32-696.10.3.el6 updates kernel.x86_64 2.6.32-696.13.2.el6 updates kernel.x86_64 2.6.32-696.16.1.el6 updates

3. If you wish to install a specific kernel, run the yum install KERNELNAME command, where KERNELNAME represents the desired kernel. Otherwise, run the yum install kernel-2.6.32 command to install the latest kernel.

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   [root@c6 ~]# yum install kernel-2.6.32 Loaded plugins: fastestmirror Setting up Install Process Loading mirror speeds from cached hostfile * base: reflector.westga.edu * epel: mirror.compevo.com * extras: ftp.osuosl.org * updates: dallas.tx.mirror.xygenhosting.com Resolving Dependencies --> Running transaction check ---> Package kernel.x86_64 0:2.6.32-696.16.1.el6 will be installed --> Finished Dependency Resolution Dependencies Resolved =================================================================================================================================================================================== Package Arch Version Repository Size =================================================================================================================================================================================== Installing: kernel x86_64 2.6.32-696.16.1.el6 updates 32 M Transaction Summary =================================================================================================================================================================================== Install 1 Package(s) Total download size: 32 M Installed size: 131 M Is this ok [y/N]: y Downloading Packages: kernel-2.6.32-696.16.1.el6.x86_64.rpm | 32 MB 00:11 Running rpm_check_debug Running Transaction Test Transaction Test Succeeded Running Transaction Installing : kernel-2.6.32-696.16.1.el6.x86_64 1/1 Verifying : kernel-2.6.32-696.16.1.el6.x86_64 1/1 Installed: kernel.x86_64 0:2.6.32-696.16.1.el6 Complete!

4. Run the reboot command to reboot your server.

5. After the server reboots, log in to your server via SSH again and run the uname -r command. The output should resemble the following:

   2.6.32-696.13.2.el6.x86_64
   

After you replace the hardened kernel, we strongly recommend that you navigate to WHM’s Security Advisor interface (WHM >> Home >> Security Center >> Security Advisor) and install KernelCare’s free symlink protection from CloudLinux™.