CVE-2022-24769
Default inheritable capabilities for linux container should be empty
En resumen
Los contenedores Docker se iniciaban con permisos Linux innecesarios (capacidades heredables) que permitían que los programas dentro de ellos ganaran privilegios adicionales. Esto creaba un entorno menos seguro donde usuarios sin privilegios podrían escalar sus permisos de formas que normalmente no podrían.
Detalle técnico
El Moby/Docker Engine anterior a la versión 20.10.14 inicializaba incorrectamente contenedores con conjuntos de capacidades heredables no vacíos, permitiendo que programas con capacidades de archivo se elevaran al conjunto permitido durante execve(2). Procesos sin privilegios podían explotar capacidades de archivo heredables para ganar privilegios hasta el bounding set del contenedor. La vulnerabilidad afectaba contenedores que dependían de separación de privilegios basada en usuario/grupo y se corrigió al resetear capacidades heredables a vacío al inicio del contenedor.
Resumen generado y traducido por IA a partir de la descripción oficial.
Moby is an open-source project created by Docker to enable and accelerate software containerization. A bug was found in Moby (Docker Engine) prior to version 20.10.14 where containers were incorrectly started with non-empty inheritable Linux process capabilities, creating an atypical Linux environment and enabling programs with inheritable file capabilities to elevate those capabilities to the permitted set during `execve(2)`. Normally, when executable programs have specified permitted file capabilities, otherwise unprivileged users and processes can execute those programs and gain the specified file capabilities up to the bounding set. Due to this bug, containers which included executable programs with inheritable file capabilities allowed otherwise unprivileged users and processes to additionally gain these inheritable file capabilities up to the container's bounding set. Containers which use Linux users and groups to perform privilege separation inside the container are most directly impacted. This bug did not affect the container security sandbox as the inheritable set never contained more capabilities than were included in the container's bounding set. This bug has been fixed in Moby (Docker Engine) 20.10.14. Running containers should be stopped, deleted, and recreated for the inheritable capabilities to be reset. This fix changes Moby (Docker Engine) behavior such that containers are started with a more typical Linux environment. As a workaround, the entry point of a container can be modified to use a utility like `capsh(1)` to drop inheritable capabilities prior to the primary process starting.
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L