What is the Docker socket (/var/run/docker.sock) and what security risk does mounting it in a container pose?

Question

Docker Fundamentals — Hard

What is the Docker socket (/var/run/docker.sock) and what security risk does mounting it in a container pose?

Accepted Answer

Mounting the Docker socket (/var/run/docker.sock) in a container gives that container full control over the Docker daemon, posing a critical security risk. This effectively grants root access to the host, allowing compromised containers to create privileged containers or escape isolation.