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Overview

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

Warning:

  • We deprecated the cPanel-provided hardened kernel in cPanel & WHM version 68 and we no longer provide updates to this kernel. We strongly recommend that you remove the hardened kernel and consider KernelCare's free symlink protection.
  • You will need to reboot your server during this procedure.

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:

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

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

    [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.

    [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.


Additional documentation