CVE-2019-19921

runc versiones hasta 1.0.0-rc9, posee un Control de Acceso Incorrecto conllevando a una escalada de privilegios, relacionado con el archivo libcontainer/rootfs_linux.go. Para explotar esto, un atacante debe ser capaz de generar dos contenedores con configuraciones de montaje de volumen personalizadas y ser capaz de ejecutar imágenes personalizadas. (Esta vulnerabilidad no afecta a Docker debido a un detalle de implementación que bloquea el ataque).

A flaw was found in runc. An attacker who controls the container image for two containers that share a volume can race volume mounts during container initialization, by adding a symlink to the rootfs that points to a directory on the volume. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.

USN-6088-1 fixed vulnerabilities in runC. This update provides the corresponding updates for Ubuntu 16.04 LTS. It was discovered that runC incorrectly performed access control when mounting /proc to non-directories. An attacker could possibly use this issue to escalate privileges. Felix Wilhelm discovered that runC incorrecly handled netlink messages. An attacker could possibly use this issue to escalate privileges.