How to use this image

All examples in this guide use the public image. If you've mirrored the repository for your own use (for example, to your Docker Hub namespace), update your commands to reference the mirrored image instead of the public one.

For example:

• Public image: dhi.io/<repository>:<tag>
• Mirrored image: <your-namespace>/dhi-<repository>:<tag>

For the examples, you must first use docker login dhi.io to authenticate to the registry to pull the images.

What's included in this socket-cli image

This Docker Hardened socket-cli image includes:

• socket -- the main CLI (scan, package score, patch, login, and more)
• socket-npm / socket-npx -- wrap npm/npx with Socket security scoring (functional in the dev variant, which ships npm)

All launchers are on PATH at /usr/local/bin, so docker run --entrypoint socket and Kubernetes command: ["socket"] work as they do after an npm i -g socket. The socket-pnpm and socket-yarn launchers are present for migration parity only -- no variant ships pnpm or yarn, so they require user-supplied tooling. The runtime variant ships only the CLI and the Node.js runtime it needs; npm and git are present only in the dev variant.

Run the container

Running the image with no arguments prints the real usage banner:

$ docker run --rm dhi.io/socket-cli:<tag>
   _____         _       _        /---------------
  |   __|___ ___| |_ ___| |_      | CLI: v1.1.160
  |__   | . |  _| '_| -_|  _|     | token: (not set), org: (not set)
  |_____|___|___|_,_|___|_|.dev   | Command: `socket`, cwd: /work

  CLI for Socket.dev

  Usage
    $ socket <command>
    $ socket scan create --json
    $ socket package score npm lodash --markdown

  Note: All commands have their own --help

Check the version:

$ docker run --rm dhi.io/socket-cli:<tag> --version
1.1.160

Authenticate with a Socket API token

Most commands (scanning, package scoring, patch application) require a Socket API token. Create one from your Socket.dev⁠ organization settings and pass it via SOCKET_CLI_API_TOKEN:

docker run --rm \
  -e SOCKET_CLI_API_TOKEN="$SOCKET_CLI_API_TOKEN" \
  -v "$PWD:/work" \
  dhi.io/socket-cli:<tag> scan create --json .

Without a token, commands that need one fail with a clear error identifying the missing requirement, for example:

$ docker run --rm dhi.io/socket-cli:<tag> package score npm/left-pad
✖  Input error:  Please review the input requirements and try again

  ✔ First parameter must be an ecosystem or the whole purl
  ✔ Expecting at least one package
  ✖ This command requires a Socket API token for access (try `socket login`)

Scan a project

Mount your project and run a scan (requires a token from an organization with API access):

docker run --rm \
  -e SOCKET_CLI_API_TOKEN="$SOCKET_CLI_API_TOKEN" \
  -v "$PWD:/work" \
  dhi.io/socket-cli:<tag> scan create --no-interactive --json .

Wrap npm/npx (dev variant)

The runtime image intentionally omits npm/git -- the socket npm/socket npx wrappers, and socket fix (which commits fix branches via git), need the dev variant:

docker run --rm \
  -e SOCKET_CLI_API_TOKEN="$SOCKET_CLI_API_TOKEN" \
  -v "$PWD:/work" \
  --entrypoint socket \
  dhi.io/socket-cli:<tag>-dev npm install

Reachability analysis and SBOM generation

socket scan create --reach, socket fix, and socket cdxgen lazily download additional tooling (@coana-tech/cli, @cyclonedx/cdxgen, synp) via npx the first time they run -- they are not bundled in the image, and the runtime variant does not ship npm/npx at all. These commands require the dev variant (which has npm and git) plus outbound network access to the npm registry. Likewise, socket manifest subcommands for other ecosystems (gradle, scala, kotlin, maven, conda) shell out to those ecosystems' own toolchains, which no variant ships -- bring them yourself in a derived image or run those subcommands outside the container.

Known limitation: socket patch on Alpine

socket patch apply depends on a prebuilt native helper binary (@socketsecurity/socket-patch) that Socket publishes for glibc platforms (including linux/arm64) but with no musl builds. The x64 binary is statically linked and has been observed to execute on Alpine, but musl is not an upstream-supported target for it -- treat socket patch on the Alpine variants as unsupported and use the Debian variants for patch workflows. Everything else in the CLI is pure JavaScript and works identically everywhere.

Non-hardened images vs. Docker Hardened Images

Socket does not publish an upstream Docker image for this CLI (socketdev/cli on Docker Hub is Socket's separate Python-based scanner, not this project), so there is no upstream container behavior to match. This image runs as the nonroot user by default (unlike a typical local npm install -g socket where the CLI runs as whatever user invokes it), and the runtime variant has no shell -- use the dev variant for interactive or wrapper use cases.

Image variants

Docker Hardened Images come in different variants depending on their intended use. Image variants are identified by their tag.

• Runtime variants are designed to run your application in production. These images are intended to be used either directly or as the FROM image in the final stage of a multi-stage build. These images typically:

  • Run as a nonroot user
  • Do not include a shell or a package manager
  • Contain only the minimal set of libraries needed to run the app

• Build-time variants typically include dev in the tag name and are intended for use in the first stage of a multi-stage Dockerfile. These images typically:

  • Run as the root user
  • Include a shell and package manager
  • Are used to build or compile applications

• FIPS variants include fips in the variant name and tag. They come in both runtime and build-time variants. These variants use cryptographic modules that have been validated under FIPS 140, a U.S. government standard for secure cryptographic operations. For example, usage of MD5 fails in FIPS variants.

To view the image variants and get more information about them, select the Tags tab for this repository, and then select a tag.

Migrate to a Docker Hardened Image

To migrate your application to a Docker Hardened Image, you must update your Dockerfile. At minimum, you must update the base image in your existing Dockerfile to a Docker Hardened Image. This and a few other common changes are listed in the following table of migration notes.

The following steps outline the general migration process.

1. Find hardened images for your app.

   A hardened image may have several variants. Inspect the image tags and find the image variant that meets your needs.

2. Update the base image in your Dockerfile.

   Update the base image in your application's Dockerfile to the hardened image you found in the previous step. For framework images, this is typically going to be an image tagged as dev because it has the tools needed to install packages and dependencies.

3. For multi-stage Dockerfiles, update the runtime image in your Dockerfile.

   To ensure that your final image is as minimal as possible, you should use a multi-stage build. All stages in your Dockerfile should use a hardened image. While intermediary stages will typically use images tagged as dev, your final runtime stage should use a non-dev image variant.

4. Install additional packages

   Docker Hardened Images contain minimal packages in order to reduce the potential attack surface. You may need to install additional packages in your Dockerfile. Inspect the image variants to identify which packages are already installed.

   Only images tagged as dev typically have package managers. You should use a multi-stage Dockerfile to install the packages. Install the packages in the build stage that uses a dev image. Then, if needed, copy any necessary artifacts to the runtime stage that uses a non-dev image.

   For Alpine-based images, you can use apk to install packages. For Debian-based images, you can use apt-get to install packages.

Troubleshooting migration

The following are common issues that you may encounter during migration.

General debugging

The hardened images intended for runtime don't contain a shell nor any tools for debugging. The recommended method for debugging applications built with Docker Hardened Images is to use Docker Debug⁠ to attach to these containers. Docker Debug provides a shell, common debugging tools, and lets you install other tools in an ephemeral, writable layer that only exists during the debugging session.

Permissions

By default image variants intended for runtime, run as the nonroot user. Ensure that necessary files and directories are accessible to the nonroot user. You may need to copy files to different directories or change permissions so your application running as the nonroot user can access them.

Privileged ports

Non-dev hardened images run as a nonroot user by default. As a result, applications in these images can't bind to privileged ports (below 1024) when running in Kubernetes or in Docker Engine versions older than 20.10. To avoid issues, configure your application to listen on port 1025 or higher inside the container, even if you map it to a lower port on the host. For example, docker run -p 80:8080 my-image will work because the port inside the container is 8080, and docker run -p 80:81 my-image won't work because the port inside the container is 81.

No shell

By default, image variants intended for runtime don't contain a shell. Use dev images in build stages to run shell commands and then copy any necessary artifacts into the runtime stage. In addition, use Docker Debug to debug containers with no shell.

Entry point

Docker Hardened Images may have different entry points than images such as Docker Official Images. Use docker inspect to inspect entry points for Docker Hardened Images and update your Dockerfile if necessary.