CVE-2019-3874

The SCTP socket buffer used by a userspace application is not accounted by the cgroups subsystem. An attacker can use this flaw to cause a denial of service attack.

While this issue affects the Linux Kernel in Red Hat Enterprise Linux, and not OpenShift Container Platform (OCP) 3 code directly. OCP 3 makes use of CGroups in the Kernel to measure and report on the amount of system resources used by an end user application.

The default Security Context Constraints (SCC) in OpenShift Container Platform 3.x disallow an end user from running a container as root. Also a check is performed by the OCP 3 Installer to ensure SELinux is enabled, [1].

[1] https://github.com/openshift/openshift-ansible/blob/006fb14e9a28df9bd1a58ac376bbdf3eba50fa51/roles/openshift_node/tasks/main.yml#L3

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

SELinux prevents a bind of the SCTP socket by a non-root user.

To mitigate this issue if not using SELinux, or if a Security Context Constraint allows running pods as the root user the 'sctp' module should be blacklisted. Please this this Knowledge Base article for more information on how to blacklist a kernel module. https://access.redhat.com/solutions/41278