Execution of malicious containers allows for container escape and access to host filesystem
CVE: CVE-2019-5736
Component: runc
CWE: CWE-672
Severity: Important
CVSS v3: 7.7/CVSS:3.0/AV:L/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:H
Release date: 2019-02-11T13:22:00+00:00

A flaw was found in the way runc handled system file descriptors when running containers. A malicious container could use this flaw to overwrite contents of the runc binary and consequently run arbitrary commands on the container host system.

Statement: The 'docker' package shipped in Red Hat Enterprise Linux 7 Extras bundles 'runc' since 'docker' starting from version 1.12. Both the 'docker' and 'runc' packages are affected by this issue.

The 'docker-latest' package is deprecated as of Red Hat Enterprise Linux 7.5. Customers using this package should update to the latest 'docker' package shipped in Red Hat Enterprise Linux 7 Extras.

OpenShift Container Platform (OCP) versions 3.9 and later use 'docker' version 1.13 in the default configuration but can be configured to use CRI-O as an alternative, which depends on the 'runc' package. OCP versions 3.9 and later should use the updated 'docker' and 'runc' packages shipped in Red Hat Enterprise Linux 7 Extras.

OCP versions 3.4 through 3.7 originally used 'docker' version 1.12 from the Red Hat Enterprise Linux 7 Extras channel. An updated version of 'docker' 1.12 has been delivered to the RPM channels for OCP versions 3.4 through 3.7.

OCP version 3.9 previously shipped a version of 'runc' in it's RPM repository. OCP 3.9 clusters using CRI-O should update 'runc' from the Red Hat Enterprise Linux 7 Extras channel.

Red Hat Enterprise Linux Atomic Host 7 is not affected by this vulnerability as the target runc binaries are stored on a read-only filesystem and cannot be overwritten.

Remediation:
Before applying this update, make sure all previously released errata relevant to your system have been applied.

See the following documentation for important instructions on how to upgrade your cluster and fully apply this asynchronous errata update.

For OpenShift Container Platform 3.4:

https://docs.openshift.com/container-platform/3.4/release_notes/ocp_3_4_release_notes.html

For OpenShift Container Platform 3.5:

https://docs.openshift.com/container-platform/3.5/release_notes/ocp_3_5_release_notes.html

For OpenShift Container Platform 3.6:

https://docs.openshift.com/container-platform/3.6/release_notes/ocp_3_6_release_notes.html

For OpenShift Container Platform 3.7:

https://docs.openshift.com/container-platform/3.7/release_notes/ocp_3_7_release_notes.html

This update is available via the Red Hat Network. Details on how to use the
Red Hat Network to apply this update are available at
https://access.redhat.com/articles/11258.
The References section of this erratum contains a link to download CDK 3.7.0-1 (you must log in to download the update).

Instructions are provided in the Red Hat Container Development Kit Getting Started Guide linked in the References section.
This vulnerability is mitigated on Red Hat Enterprise Linux 7 if SELinux is in enforcing mode. SELinux in enforcing mode is a pre-requisite for OpenShift Container Platform 3.x.