CVE-2021-41091
Insufficiently restricted permissions on data directory in Docker Engine
En resumen
Docker Engine tenía permisos débiles en su directorio de datos, permitiendo que usuarios comunes accedieran, ejecutaran y modificaran archivos pertenecientes a contenedores. Esto podría permitir que usuarios regulares ejecuten programas privilegiados o accedan a datos sensibles del contenedor.
Detalle técnico
Moby (Docker Engine) no restringió adecuadamente los permisos en los subdirectorios de `/var/lib/docker`, permitiendo que usuarios locales sin privilegios recorran directorios, ejecuten binarios setuid desde contenedores o lean/modifiquen archivos en caso de colisión de UID/GID entre contextos de host y contenedor. La explotación requiere acceso local al host y depende de configuraciones de permisos ejecutables y asignación de UID en contenedores.
Resumen generado y traducido por IA a partir de la descripción oficial.
Moby is an open-source project created by Docker to enable software containerization. A bug was found in Moby (Docker Engine) where the data directory (typically `/var/lib/docker`) contained subdirectories with insufficiently restricted permissions, allowing otherwise unprivileged Linux users to traverse directory contents and execute programs. When containers included executable programs with extended permission bits (such as `setuid`), unprivileged Linux users could discover and execute those programs. When the UID of an unprivileged Linux user on the host collided with the file owner or group inside a container, the unprivileged Linux user on the host could discover, read, and modify those files. This bug has been fixed in Moby (Docker Engine) 20.10.9. Users should update to this version as soon as possible. Running containers should be stopped and restarted for the permissions to be fixed. For users unable to upgrade limit access to the host to trusted users. Limit access to host volumes to trusted containers.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:L