Blocks (some rules ask) when a change to a Dockerfile, Containerfile or compose file adds: a base image with no tag, latest, an unresolvable ARG or no digest (stage-aware: FROM or COPY --from a stage is not an image); a final stage running as root; TLS or package-signature checks off; secret-named ENV/ARG/environment literals; COPY of key or .env files; remote ADD without checksum; fetch piped to a shell; RUN --security=insecure; chmod 777 or setuid; sudo, sshd, chpasswd; unpinned git clone; ...
Installs into .claude/skills of the current project.
Are you the author of Dockerfile Compose Security?
Add the live security badge to your README. It updates with every re-scan.
[](https://www.skillsdirectory.com/skills/open-coder-ai-dockerfile-compose-security)
---
name: dockerfile-compose-security
description: "Blocks (some rules ask) when a change to a Dockerfile, Containerfile or compose file adds: a base image with no tag, latest, an unresolvable ARG or no digest (stage-aware: FROM or COPY --from a stage is not an image); a final stage running as root; TLS or package-signature checks off; secret-named ENV/ARG/environment literals; COPY of key or .env files; remote ADD without checksum; fetch piped to a shell; RUN --security=insecure; chmod 777 or setuid; sudo, sshd, chpasswd; unpinned git clone; ONBUILD RUN; compose privileged, broad cap_add, unconfined profiles, devices, host namespaces, runtime socket or host-root mounts, database ports on every interface, untagged images. A one-line form is left to block-fetch-exec-in-files, block-unpinned-agent-components or agentic-code-security only where that gate is installed and reads the file; scan-secrets lines always. Misses: build args overriding defaults, commands in variables, aliases or $'' quoting, bake and k8s files. Friction, not a boundary."
metadata:
chock.artifact: rule
chock.enforcement: block
chock.coverage_without_chock: advisory
---
# Dockerfile and Compose Security
Blocks (some rules ask) when a change to a Dockerfile, Containerfile or compose file adds: a base image with no tag, latest, an unresolvable ARG or no digest (stage-aware: FROM or COPY --from a stage is not an image); a final stage running as root; TLS or package-signature checks off; secret-named ENV/ARG/environment literals; COPY of key or .env files; remote ADD without checksum; fetch piped to a shell; RUN --security=insecure; chmod 777 or setuid; sudo, sshd, chpasswd; unpinned git clone; ONBUILD RUN; compose privileged, broad cap_add, unconfined profiles, devices, host namespaces, runtime socket or host-root mounts, database ports on every interface, untagged images. A one-line form is left to block-fetch-exec-in-files, block-unpinned-agent-components or agentic-code-security only where that gate is installed and reads the file; scan-secrets lines always. Misses: build args overriding defaults, commands in variables, aliases or $'' quoting, bake and k8s files. Friction, not a boundary.
```
flag(container_change): Dockerfile|Containerfile|compose adds floating/undigested image, root final stage, TLS|signature off, literal secret, key-file COPY, privileged|cap_add|host ns|docker.sock|host-root mount, db port on 0.0.0.0
prefer: pinned tag@sha256, USER <uid>, RUN --mount=type=secret, cap_add narrow, named volumes; waiver: '# chock: allow <rule-id>', person only
```
This skill is advisory: the client reading it has no mechanism to enforce it. The same policy compiled by `chock` blocks at commit, on an agent's file writes and at turn end. See https://github.com/open-coder-ai/chock
