Chapter 8. Applying security policies

During the in-place upgrade process, certain security policies must remain disabled. Furthermore, RHEL 8 introduces a new concept of system-wide cryptographic policies and also security profiles might contain changes between major releases. To make your system more secure, switch SELinux to enforcing mode and set a system-wide cryptographic policy. You may also want to remediate the system to be compliant with a specific security profile.

8.1. Changing SELinux mode to enforcing

During the in-place upgrade process, the Leapp utility sets SELinux mode to permissive. When the system is successfully upgraded, you have to manually change SELinux mode to enforcing.

Prerequisites

Procedure

  1. Ensure that there are no SELinux denials, for example, by using the ausearch utility: 

    # ausearch -m AVC,USER_AVC -ts boot

    Note that the previous step covers only the most common scenario. To check for all possible SELinux denials, see the Identifying SELinux denials section in the Using SELinux title, which provides a complete procedure.

  2. Open the /etc/selinux/config file in a text editor of your choice, for example: 

    # vi /etc/selinux/config

  3. Configure the SELINUX=enforcing option: 

    # This file controls the state of SELinux on the system.
# SELINUX= can take one of these three values:
#       enforcing - SELinux security policy is enforced.
#       permissive - SELinux prints warnings instead of enforcing.
#       disabled - No SELinux policy is loaded.
SELINUX=enforcing
# SELINUXTYPE= can take one of these two values:
#       targeted - Targeted processes are protected,
#       mls - Multi Level Security protection.
SELINUXTYPE=targeted

  4. Save the change, and restart the system: 

    # reboot

Verification

  1. After the system restarts, confirm that the getenforce command returns Enforcing: 

    $ getenforce
Enforcing

Additional resources

8.2. Setting system-wide cryptographic policies

The system-wide cryptographic policies is a system component that configures the core cryptographic subsystems, covering the TLS, IPSec, SSH, DNSSec, and Kerberos protocols.

After a successful installation or an in-place upgrade process, the system-wide cryptographic policy is automatically set to DEFAULT. The DEFAULT system-wide cryptographic policy level offers secure settings for current threat models.

To view or change the current system-wide cryptographic policy, use the update-crypto-policies tool: 

$ update-crypto-policies --show
DEFAULT

For example, the following command switches the system-wide crypto policy level to FUTURE, which should withstand any near-term future attacks: 

# update-crypto-policies --set FUTURE
Setting system policy to FUTURE

You can also customize system-wide cryptographic policies. For details, see the Customizing system-wide cryptographic policies with subpolicies and Creating and setting a custom system-wide cryptographic policy sections.

Additional resources

8.3. Upgrading the system hardened to a security baseline

To get a fully hardened system after a successful upgrade to RHEL 8, you can use automated remediation provided by the OpenSCAP suite. OpenSCAP remediations align your system with security baselines, such as PCI-DSS, OSPP, or ACSC Essential Eight. The configuration compliance recommendations differ among major versions of Red Hat Enterprise Linux due to the evolution of the security offering.

When upgrading a hardened RHEL 7 system, the Leapp tool does not provide direct means to retain the full hardening. Depending on the changes in the component configuration, the system might diverge from the recommendations for the RHEL 8 during the upgrade.

Note

You cannot use the same SCAP content for scanning RHEL 7 and RHEL 8. Update the management platforms if the compliance of the system is managed by the tools like Red Hat Satellite or Red Hat Insights.

As an alternative to automated remediations, you can make the changes manually by following an OpenSCAP-generated report. For information about generating a compliance report, see Scanning the system for security compliance and vulnerabilities.

Follow the procedure to automatically harden your system with the PCI-DSS profile.

Important

Automated remediations support RHEL systems in the default configuration. Because the system upgrade has been altered after the installation, running remediation might not make it fully compliant with the required security profile. You might need to fix some requirements manually.

Prerequisites

  • The scap-security-guide package is installed on your RHEL 8 system.

Procedure

  1. Find the appropriate security compliance data stream .xml file: 

    $ ls /usr/share/xml/scap/ssg/content/
ssg-firefox-cpe-dictionary.xml  ssg-rhel6-ocil.xml
ssg-firefox-cpe-oval.xml        ssg-rhel6-oval.xml
...
ssg-rhel6-ds-1.2.xml          ssg-rhel8-oval.xml
ssg-rhel8-ds.xml              ssg-rhel8-xccdf.xml
...

    For additional information, see section Viewing compliance profiles.

  2. Remediate the system according to the selected profile from the appropriate data stream: 

    # oscap xccdf eval --profile pci-dss --remediate /usr/share/xml/scap/ssg/content/ssg-rhel8-ds.xml

    You can replace the pci-dss value in the --profile argument with the ID of the profile according to which you want to harden your system. For a full list of profiles supported in RHEL 8, see SCAP security profiles supported in RHEL.

    Warning

    If not used carefully, running the system evaluation with the Remediate option enabled might render the system non-functional. Red Hat does not provide any automated method to revert changes made by security-hardening remediations. Remediations are supported on RHEL systems in the default configuration. If your system has been altered after the installation, running remediation might not make it compliant with the required security profile.

  3. Restart your system: 

    # reboot

Verification

  1. Verify that the system is compliant with the profile, and save the results in an HTML file: 

    $ oscap xccdf eval --report pcidss_report.html --profile pci-dss /usr/share/xml/scap/ssg/content/ssg-rhel8-ds.xml

Additional resources