CVE-2022-24769
Default inheritable capabilities for linux container should be empty
Em resumo
Contêineres Docker eram iniciados com permissões Linux desnecessárias (capacidades herdáveis) que permitiam que programas dentro deles ganhassem privilégios extras. Isso criava um ambiente menos seguro onde usuários sem privilégios poderiam escalar suas permissões de formas que normalmente não conseguiriam.
Detalhe técnico
O Moby/Docker Engine anterior à versão 20.10.14 inicializava incorretamente contêineres com conjuntos de capacidades herdáveis não vazios, permitindo que programas com capacidades de arquivo se elevassem ao conjunto permitido durante execve(2). Processos sem privilégios podiam explorar capacidades de arquivo herdáveis para ganhar privilégios até o bounding set do contêiner. A vulnerabilidade afetava contêineres que dependiam de separação de privilégios baseada em usuário/grupo e foi corrigida ao resetar capacidades herdáveis para vazio no inicío do contêiner.
Resumo gerado e traduzido por IA a partir da descrição 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