There are tools you can use to scan and track the contents of your downloaded and deployed container images. However, there are many public sources of container images. When using public container registries, you can add a layer of protection by using trusted sources.
Consuming security updates is particularly important when managing immutable containers. Immutable containers are containers that will never be changed while running. When you deploy immutable containers, you do not step into the running container to replace one or more binaries; you rebuild and redeploy an updated container image.
Red Hat certified images are:
Free of known vulnerabilities in the platform components or layers.
Compatible across the RHEL platforms, from bare metal to cloud.
Supported by Red Hat.
The list of known vulnerabilities is constantly evolving, so you must track the contents of your deployed container images, as well as newly downloaded images, over time. You can use Red Hat Security Advisories (RHSAs) to alert you to any newly discovered issues in Red Hat certified container images, and direct you to the updated image.
Red Hat provides certified containers for Red Hat products and partner offerings via the Red Hat Registry, which is a public container registry hosted by Red Hat at registry.access.redhat.com. The Red Hat Container Catalog enables you to identify bug fix or security advisories associated with container images provided in the Red Hat Registry.
Container content is monitored for vulnerabilities by Red Hat and updated regularly. When Red Hat releases security updates, such as fixes to glibc, Drown, or Dirty Cow, any affected container images are also rebuilt and pushed to the Red Hat Registry.
Red Hat uses a "health index" for security risk with containers provided through the Red Hat Container Catalog. These containers consume software provided by Red Hat and the errata process, so old, stale containers are insecure whereas new, fresh containers are more secure.
To illustrate the age of containers, the Red Hat Container Catalog uses a grading system. A freshness grade is a measure of the oldest and most severe security errata available for an image. "A" is more up-to-date than "F". See Container Health Index grades as used inside the Red Hat Container Catalog for more details on this grading system.
OpenShift Container Platform includes the OpenShift Container Registry, a private registry that runs integrated with the platform that you can use to manage your container images. The OpenShift Container Registry provides role-based access controls that allow you to manage who can pull and push which container images.
OpenShift Container Platform also supports integration with other private registries you may already be using.
OpenShift Container Platform Architecture: Infrastructure Components → Image Registry