Red Hat announced a vulnerability this morning – one that can be exploited if a user runs malicious or modified containers. The flaw in runC (a lightweight portable container runtime) and Docker that this vulnerability exposes allows an attacker to escape a container and access the underlying file system. That might sound bad, but there's more.
The good news is that this vulnerability cannot be exploited if SELinux is enabled and that this is the default on Red Hat systems. To check whether your Red Hat system is enforcing SELinux, use one of the following commands:
$ /usr/sbin/getenforce Enforcing <==
$ sestatus SELinux status: enabled <== SELinuxfs mount: /sys/fs/selinux SELinux root directory: /etc/selinux Loaded policy name: targeted Current mode: enforcing Mode from config file: enforcing Policy MLS status: enabled Policy deny_unknown status: allowed Memory protection checking: actual (secure) Max kernel policy version: 31
This vulnerability also requires local access to the system. Affected Red Hat systems include: