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Purpose / Other

Multi Stage Dockerfile Skill Security Audit

What the author says it does (original text)

Create optimized multi-stage Dockerfiles for any language or framework

Independent security check

Security risks found

Files checked
1
Risks found
1
Could it run dangerous commands?Looks for programs run straight after downloading, remote control of your computer, and hidden commands.Risks found: 1
Medium risk

Version tags do not guarantee reproducible base images

Source references: 1
What we found

The Skill claims a tag such as `python:3.11-slim` ensures reproducible builds, but container tags can normally be moved to different images. It does not require pinning an immutable image digest.

Why this matters

The same Dockerfile may pull different code and system packages over time. If an upstream tag is mistakenly changed or its supply chain is compromised, builds could also execute unexpected base-image content.

The guidance says a tag such as `python:3.11-slim` “ensure[s] reproducible builds,” but such tags are not immutable identifiers: the publisher can update the image they reference, causing the same Dockerfile to fetch different content. If relied upon for supply-chain or vulnerability auditing, builds may change without a Dockerfile change. The user can ask the author to require digest pinning and clarify that tags only constrain versions.

SKILL.md:19In the instructionsOpen original file
- Start with official, minimal base images when possible- Specify exact version tags to ensure reproducible builds (e.g., `python:3.11-slim` not just `python`)- Consider distroless images for runtime stages where appropriate
Could it expose your files or keys?Looks for uploads of files containing passwords or keys, and keys written directly in the code.No risks found
Could it delete files or keep running?Looks for broad file deletion, disk overwrites, and programs set to start automatically.No risks found
Could it bypass safety checks?Looks for skipped website security checks, excessive file access, or actions that skip your approval.No risks found
Could it mislead the AI or hide text?Checks the skill instructions for requests to ignore you, influence the report, or hide text in invisible characters.No risks found
Could it change links or payment recipients without asking?Looks for forced referral or payment changes combined with instructions to hide the change.No risks found

Inside this skill

5 instruction sections

The Skill directs the agent to perform compilation, dependency installation, and testing in earlier stages, then copy only runtime artifacts into the final image to reduce included tools and files.

View source
SKILL.md:10In the instructionsOpen original file
- Use a builder stage for compilation, dependency installation, and other build-time operations- Use a separate runtime stage that only includes what's needed to run the application- Copy only the necessary artifacts from the builder stage to the runtime stage- Use meaningful stage names with the `AS` keyword (e.g., `FROM node:18 AS builder`)- Place stages in logical order: dependencies → build → test → runtime

It recommends official minimal base images, a non-root runtime user, restrictive file permissions, and excluding build tools and build secrets from the final image.

View source
SKILL.md:18In the instructionsOpen original file
- Start with official, minimal base images when possible- Specify exact version tags to ensure reproducible builds (e.g., `python:3.11-slim` not just `python`)- Consider distroless images for runtime stages where appropriate- Use Alpine-based images for smaller footprints when compatible with your application- Ensure the runtime image has the minimal necessary dependencies
SKILL.md:34In the instructionsOpen original file
- Avoid running containers as root - use `USER` instruction to specify a non-root user- Remove build tools and unnecessary packages from the final image- Scan the final image for vulnerabilities- Set restrictive file permissions- Use multi-stage builds to avoid including build secrets in the final image
Start here · InstructionsSKILL.md
multi-stage-dockerfile
Lines connect the instruction file to its sections, not an observed execution order. Select a section to read the source.
Files and check records1 files

Coverage and gaps

Content covered in each file

These are the source ranges included in this check, not a guarantee that every issue has been resolved.

  • SKILL.mdFull text included

This report is for the version above. We read the available code and instructions without running the skill or checking extra packages it installs. This is not a promise of safety: a different version or setup may behave differently.

  • SKILL.mdInstructions
Lines read
47
File checksum (to compare versions)
e4ea8df9d1f0f65f43afd84b10e1aee86c820eef1091781e7225b8df3288eae6