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The Symlink Protection patchset is available for free for CentOS 6 & 7, even if you are not running KernelCare

The Symlink Protection patchset is available for free for CentOS 6 & 7, even if you are not running KernelCare

A few weeks ago we released the KernelCare "Extra" Patchset with the security fixes and the symlink protection available to all KernelCare customers running CentOS kernels. Today we are pleased to share that you can get the Symlink Protection Patchset for CentOS 6 and 7 at no cost, even if you don’t have licenses of KernelCare.

We’ve been discussing with the cPanel team on how to help with hardening of their customers' system kernels. This Symlink Protection Patchset will protect CentOS 6 and 7 systems and will help defend shared hosting servers, including the cPanel servers, against symlink attacks.

A symlink race attack is frequently used against shared hosting servers. It allows a malicious user to serve files that belong to other users by creating a symbolic link to those files. It is often used to access config.php files that belong to others. This patchset helps protect against such attacks.

Note that this patchset includes only the symlink protection, and does not include the security fixes (those are available to KernelCare customers) - you will still need to update kernel and REBOOT each time new CentOS kernel is released to keep your kernel secure.

We recommend the installation of this patchset on CentOS 6 and CentOS 7 to make your servers more secure.

How to install the free symlink protection patchset:

Below we provide instructions on how to install KernelCare and run this patchset for free. Though this symlink protection patchset is part of KernelCare, it does not require you to purchase a license or even register for the KernelCare free trial (if you choose to purchase a license at a later date, information on how to upgrade will be published in the documentation soon).

To enable the symlink protection, perform the following steps:

First, install KernelCare client:

curl -s https://repo.cloudlinux.com/kernelcare/kernelcare_install.sh | bash

Enable free patch type, this patch type doesn't require a license

kcarectl --set-patch-type free --update

The ‘free’ patch will be applied on the next update.

. . .

During the installation, you should see something similar to:


OS: CentOS6
kernel: kernel-2.6.32-696.el6
time: 2017-06-22 16:13:40
uname: 2.6.32-642.15.1.el6

kpatch-name: 2.6.32/symlink-protection.patch
kpatch-description: symlink protection // If you see this patch, it mean that you can enable symlink protection.
kpatch-kernel: kernel-2.6.32-279.2.1.el6
kpatch-cve: N/A
kpatch-cvss: N/A
kpatch-cve-url: N/A
kpatch-patch-url: https://gerrit.cloudlinux.com/#/c/16508/

kpatch-name: 2.6.32/symlink-protection.kpatch-1.patch
kpatch-description: symlink protection (kpatch adaptation)
kpatch-kernel: kernel-2.6.32-279.2.1.el6
kpatch-cve: N/A
kpatch-cvss: N/A
kpatch-cve-url: N/A
kpatch-patch-url: https://gerrit.cloudlinux.com/#/c/16508/


Edit the file /etc/sysconfig/kcare/sysctl.conf (or create it if it doesn't exist) - add the lines:

fs.enforce_symlinksifowner = 1
fs.symlinkown_gid = 48


Execute:

sysctl -w fs.enforce_symlinksifowner=1
sysctl -w fs.symlinkown_gid=48

Note: On standard RPM Apache installation, Apache is usually running under GID 48. On cPanel servers, Apache is running under user nobody, GID 99.

Click here to learn more about KernelCare.
 

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Comments 110

Guest - Saleh Ahmed on Tuesday, 17 July 2018 12:49

[email protected] ~]# kcarectl --set-patch-type free --update
'free' patch type is unavailable for current kernel
[[email protected] ~]#


Kernel 3.10.0-862.6.3.el7.x86_64

[email protected] ~]# kcarectl --set-patch-type free --update 'free' patch type is unavailable for current kernel [[email protected] ~]# Kernel 3.10.0-862.6.3.el7.x86_64
Irina Semenova on Tuesday, 17 July 2018 13:25

Free and Extra patches were added for that kernel today.

Free and Extra patches were added for that kernel today.
Irina Semenova on Tuesday, 17 July 2018 13:27

If you still have this message - please contact our support and we will investigate your problem

If you still have this message - please contact our support and we will investigate your problem
Guest - Youssef B. on Tuesday, 17 July 2018 21:03

Error on CentOS 7 x64 :

[[email protected] ~]# kcarectl --set-patch-type free --update
'free' patch type is unavailable for current kernel

Error on CentOS 7 x64 : [[email protected] ~]# kcarectl --set-patch-type free --update [b]'free' patch type is unavailable for current kernel[/b]
Guest - Elizabeta on Wednesday, 18 July 2018 11:38

Hello,

I have RHEL 7

[[email protected] ~]# kcarectl --set-patch-type free --update
'free' patch type is unavailable for current kernel

kernel 3.10.0-862.9.1.el7.x86_64

[[email protected] kcare]# kcarectl --info
kpatch-state: patch is applied
kpatch-for: Linux version 3.10.0-862.9.1.el7.x86_64 ([email protected]) (gcc version 4.8.5 20150623 (Red Hat 4.8.5-28) (GCC) ) #1 SMP Wed Jun 27 04:30:39 EDT 2018
kpatch-build-time: Tue Jul 17 22:40:29 2018
kpatch-description: 2-;3.10.0-862.9.1.el7

I would like to know, is free patch installed or trial Extra Patch from KernelCare??

Thanks in advance :-)

Hello, I have RHEL 7 [[email protected] ~]# kcarectl --set-patch-type free --update 'free' patch type is unavailable for current kernel kernel 3.10.0-862.9.1.el7.x86_64 [[email protected] kcare]# kcarectl --info kpatch-state: patch is applied kpatch-for: Linux version 3.10.0-862.9.1.el7.x86_64 ([email protected]) (gcc version 4.8.5 20150623 (Red Hat 4.8.5-28) (GCC) ) #1 SMP Wed Jun 27 04:30:39 EDT 2018 kpatch-build-time: Tue Jul 17 22:40:29 2018 kpatch-description: 2-;3.10.0-862.9.1.el7 I would like to know, is free patch installed or trial Extra Patch from KernelCare?? Thanks in advance :-)
Irina Semenova on Wednesday, 18 July 2018 12:41

Extra and Free patches are available only for CentOS 6 and 7, not for RHEL
So trial patches of KernelCare were applied

Extra and Free patches are available only for CentOS 6 and 7, not for RHEL So trial patches of KernelCare were applied
Guest - Elizabeta on Wednesday, 18 July 2018 11:58

Hello,

Just one info:

I have manually cretaed sysctl.conf file and add this:
fs.enforce_symlinksifowner = 1
fs.symlinkown_gid = 48

I have ran
[[email protected] kcare]# sysctl -w fs.enforce_symlinksifowner=1
sysctl: cannot stat /proc/sys/fs/enforce_symlinksifowner:There is no this file

Could you help me?

Best regards,
Elizabeta

Hello, Just one info: I have manually cretaed sysctl.conf file and add this: fs.enforce_symlinksifowner = 1 fs.symlinkown_gid = 48 I have ran [[email protected] kcare]# sysctl -w fs.enforce_symlinksifowner=1 sysctl: cannot stat /proc/sys/fs/enforce_symlinksifowner:There is no this file Could you help me? Best regards, Elizabeta
Guest - Elizabeta on Wednesday, 18 July 2018 13:46

Hello,

Thank you Irina for your explanation.

Best regards,
Elizabeta

Hello, Thank you Irina for your explanation. Best regards, Elizabeta
Guest - Salhidiq on Thursday, 23 August 2018 09:30

Hello, this didnt work for me, please see below:

[[email protected] ~]# kcarectl --set-patch-type free
Unknown Kernel (CentOS Linux 3.10.0-862.11.6.el7.x86_64)

[[email protected] ~]# kcarectl --info
Unknown kernel (CentOS Linux 3.10.0-862.11.6.el7.x86_64), no patches available

Hello, this didnt work for me, please see below: [[email protected] ~]# kcarectl --set-patch-type free Unknown Kernel (CentOS Linux 3.10.0-862.11.6.el7.x86_64) [[email protected] ~]# kcarectl --info Unknown kernel (CentOS Linux 3.10.0-862.11.6.el7.x86_64), no patches available
Alexandre Parubochyi on Thursday, 23 August 2018 21:15

We are going to release KernelCare patches for 3.10.0-862.11.6.el7.x86_64 tomorrow.

We are going to release KernelCare patches for 3.10.0-862.11.6.el7.x86_64 tomorrow.
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