Critical runC Container Escape Vulnerability (CVE-2019-5736) Threat Alert

• Overview

RUNC is a CLI tool for spawning and running containers according to the Open Container Initiative (OCI) specification. As the core of the Docker, runC can be called for creating, running, and destructing containers.

Recently, runC, as used in Docker before 18.09.2, has been found to contain a critical vulnerability (CVE-2019-5736), which allows attackers to overwrite the runC binary on the host and consequently execute arbitrary commands on the host with root privileges. To exploit this vulnerability, there must be either of the following types of containers: (1) a new container with an attacker-controlled image; (2) an existing container, to which the attacker previously had write access, that can be attached with docker exec. Now, new versions to fix this vulnerability are available on GitHub.

Reference links:

https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-5736

https://github.com/opencontainers/runc/commit/0a8e4117e7f715d5fbeef398405813ce8e88558b

• Scope of Impact

• Solution

To fix this vulnerability, it is recommended that all container images be audited and trusted and that runC technical developers develop their software versions as soon as possible.

To fix the runC vulnerability, visit the following GitHub link:

https://github.com/opencontainers/runc/commit/0a8e4117e7f715d5fbeef398405813ce8e88558b

This vulnerability has been fixed in Docker 18.09.2. Users are advised to upgrade Docker to 18.09.2 by downloading the update from the following link:

https://github.com/docker/docker-ce/releases/tag/v18.09.2

For the Red Hat platform, visit the following link:

https://access.redhat.com/zh_CN/security/vulnerabilities/3907161

For the AWS platform, visit the following link:

https://aws.amazon.com/cn/security/security-bulletins/AWS-2019-002/

For Kubernetes, visit the following link:

https://kubernetes.io/blog/2019/02/11/runc-and-cve-2019-5736/

• Statement

This advisory is only used to describe a potential risk. NSFOCUS does not provide any commitment or promise on this advisory. NSFOCUS and the author will not bear any liability for any direct and/or indirect consequences and losses caused by transmitting and/or using this advisory. NSFOCUS reserves all the rights to modify and interpret this advisory. Please include this statement paragraph when reproducing or transferring this advisory. Do not modify this advisory, add/delete any information to/from it, or use this advisory for commercial purposes without permission from NSFOCUS.

• About NSFOCUS

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