Slither Action

This action allows you to run the Slither static analyzer against your project, from within a GitHub Actions workflow.

To learn more about Slither itself, visit its GitHub repository and wiki pages.

• How to use
• Github Code Scanning integration
• Examples

How to use

Create .github/workflows/slither.yml:

name: Slither Analysis
on: [push]
jobs:
  analyze:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: crytic/[email protected]

Options

Key	Description
ignore-compile	If set to true, the Slither action will not attempt to compile the project. False by default. See Advanced compilation.
fail-on	Cause the action to fail if Slither finds any issue of this severity or higher. See action fail behavior.
node-version	The version of node to use. If this field is not set, the latest version will be used.
sarif	If provided, the path of the SARIF file to produce, relative to the repo root (see Github Code Scanning integration).
slither-args	Extra arguments to pass to Slither.
slither-config	The path to the Slither configuration file. By default, ./slither.config.json is used if present. See Configuration file.
slither-version	The version of slither-analyzer to use. By default, the latest release in PyPI is used.
slither-plugins	A requirements.txt file to install with pip alongside Slither. Useful to install custom plugins.
solc-version	The version of solc to use. If this field is not set, the version will be guessed from project metadata. This only has an effect if you are not using a compilation framework for your project -- i.e., if target is a standalone .sol file.
target	The path to the root of the project to be analyzed by Slither. It can be a directory or a file, and it defaults to the repo root.

Advanced compilation

If the project requires advanced compilation settings or steps, set ignore-compile to true and follow the compilation steps before running Slither. You can find an example workflow that uses this option in the examples section.

Action fail behavior

The Slither action supports a fail-on option, based on the --fail-* flags added in Slither 0.8.4. To maintain the current action behavior, this option defaults to all. The following table summarizes the action behavior across different Slither versions. You may adjust this option as needed for your workflows. If you are setting these options on your config file, set fail-on: config to prevent the action from overriding your settings.

fail-on	Slither <= 0.8.3	Slither > 0.8.3
all / pedantic	Fail on any finding	Fail on any finding
low	Fail on any finding	Fail on any finding >= low
medium	Fail on any finding	Fail on any finding >= medium
high	Fail on any finding	Fail on any finding >= high
none	Do not fail on findings †	Do not fail on findings
config	Determined by config file	Determined by config file

† Note that if you use fail-on: none with Slither 0.8.3 or earlier, certain functionality may not work as expected. In particular, Slither will not produce a SARIF file in this case. If you require fail-on: none behavior with the SARIF integration, consider adding continue-on-error: true instead to the action step.

Using a different Slither version

If the latest Slither release has a bug that does not let you analyze your project, you may want to use a different Slither version. The action lets you use an older version (or, if a fix is available, an unreleased Slither version) to analyze your code. You can use the slither-version option to specify a custom Slither release. This option can take different values:

• a slither-analyzer PyPI release version number (e.g. "0.8.3"). Slither will be installed from PyPI in this case.
• a Git ref from crytic/slither such as a branch, tag, or full commit hash (e.g. "dev", "refs/heads/dev", "refs/tags/0.8.3" or "f962d6c4eefcd4d5038a781875b826948f222b31"). Slither will be installed from source in this case.

Triaging results

Add // slither-disable-next-line DETECTOR_NAME before the finding, or use the Github Code Scanning integration.

Staying up to date

We suggest enabling Dependabot version updates for actions to get notified of new action releases. You can do so by creating .github/dependabot.yml in your repository with the following content:

version: 2
updates:
  - package-ecosystem: "github-actions"
    directory: "/"
    schedule:
      interval: "daily"

Github Code Scanning integration

The action supports the Github Code Scanning integration, which will push Slither's alerts to the Security tab of the Github project (see About code scanning). This integration eases the triaging of findings and improves the continuous integration.

Code Scanning preview

Findings Summary

Findings Details

How to use

To enable the integration, use the sarif option, and upload the Sarif file to codeql-action:

name: Slither Analysis
on: [push]
jobs:
  analyze:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4

      - name: Run Slither
        uses: crytic/[email protected]
        id: slither
        with:
          sarif: results.sarif
          fail-on: none

      - name: Upload SARIF file
        uses: github/codeql-action/upload-sarif@v3
        with:
          sarif_file: ${{ steps.slither.outputs.sarif }}

Here:

• fail-on: none is required to let the SARIF upload step run if Slither finds issues
• id: slither is the name used to reference the step later on (e.g., in steps.slither.outputs.sarif)

Examples

Example workflow: simple action

The following is a complete GitHub Actions workflow example. It will trigger on pushes to the repository, and leverage the Node.js integration in the Slither action to install the latest node version, install dependencies, and build the project that lives in src/. Once that is complete, Slither will run its analysis. The workflow will fail if findings are found.

name: Slither Analysis
on: [push]
jobs:
  analyze:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: crytic/[email protected]
        with:
          target: 'src/'

Example workflow: Hardhat and SARIF

The following is a complete GitHub Actions workflow example. It will trigger with commits on main as well as any pull request opened against the main branch. It leverages the NodeJS integration in the Slither action to set up NodeJS 16.x and install project dependencies before running Slither on the project. Slither will output findings in SARIF format, and those will get uploaded to GitHub.

We include fail-on: none on the Slither action to avoid failing the run if findings are found.

name: Slither Analysis

on:
  push:
    branches: [ main ]
  pull_request:
    branches: [ main ]

jobs:
  analyze:
    runs-on: ubuntu-latest
    permissions:
      contents: read
      security-events: write
    steps:
    - name: Checkout repository
      uses: actions/checkout@v4

    - name: Run Slither
      uses: crytic/[email protected]
      id: slither
      with:
        node-version: 16
        sarif: results.sarif
        fail-on: none

    - name: Upload SARIF file
      uses: github/codeql-action/upload-sarif@v3
      with:
        sarif_file: ${{ steps.slither.outputs.sarif }}

Example workflow: Brownie and SARIF

The following is a complete GitHub Actions workflow example. It will trigger with commits on main as well as any pull request opened against the main branch. It leverages the Python integration in the Slither action to set up a virtual environment and install project dependencies before running Slither on the project. Slither will output findings in SARIF format, and those will get uploaded to GitHub.

We also include fail-on: none on the Slither action to avoid failing the run if findings are found.

name: Slither Analysis

on:
  push:
    branches: [ main ]
  pull_request:
    branches: [ main ]

jobs:
  analyze:
    runs-on: ubuntu-latest
    permissions:
      contents: read
      security-events: write
    steps:
    - name: Checkout repository
      uses: actions/checkout@v4

    - name: Run Slither
      uses: crytic/[email protected]
      id: slither
      with:
        sarif: results.sarif
        fail-on: none

    - name: Upload SARIF file
      uses: github/codeql-action/upload-sarif@v3
      with:
        sarif_file: ${{ steps.slither.outputs.sarif }}

Example workflow: Dapp

The following is a complete GitHub Actions workflow example meant to illustrate the usage of the Slither action when the compilation framework is not based on Node or Python. It will trigger with commits on main as well as any pull request opened against the main branch. To be able to build the project, it will configure Node and Nix on the runner and install project dependencies. Once the environment is ready, it will build the project (using make build via nix-shell) and finally run Slither on the project using the GitHub action.

In this example, we leverage ignore-compile to avoid building the project as part of the Slither action execution. Slither will expect the project to be pre-built when this option is set. This allows us to use compilation frameworks that are not Node or Python-based, such as Dapp, together with the Slither action.

name: Slither Analysis

on:
  push:
    branches: [ main ]
  pull_request:
    branches: [ main ]

jobs:
  analyze:
    runs-on: ubuntu-latest
    steps:
    - name: Checkout repository
      uses: actions/checkout@v4
      with:
          submodules: recursive

    - name: Set up Node
      uses: actions/setup-node@v4

    - name: Install Yarn
      run: npm install --global yarn

    - name: Install Nix
      uses: cachix/install-nix-action@v26

    - name: Configure Cachix
      uses: cachix/cachix-action@v14
      with:
        name: dapp

    - name: Install dependencies
      run: nix-shell --run 'make'

    - name: Build the contracts
      run: nix-shell --run 'make build'

    - name: Run Slither
      uses: crytic/[email protected]
      with:
        ignore-compile: true

Example workflow: Markdown report

The following GitHub Actions workflow example will create/update pull requests with the contents of Slither's Markdown report. Useful for when GitHub Advanced Security (required for the SARIF feature) is unavailable.

name: Slither Analysis

on:
  push:
    branches: [ master ]
  pull_request:

jobs:
  analyze:
    runs-on: ubuntu-latest
    steps:
    - name: Checkout repository
      uses: actions/checkout@v4

    - name: Run Slither
      uses: crytic/[email protected]
      id: slither
      with:
        node-version: 16
        fail-on: none
        slither-args: --checklist --markdown-root ${{ github.server_url }}/${{ github.repository }}/blob/${{ github.sha }}/

    - name: Create/update checklist as PR comment
      uses: actions/github-script@v7
      if: github.event_name == 'pull_request'
      env:
        REPORT: ${{ steps.slither.outputs.stdout }}
      with:
        script: |
          const script = require('.github/scripts/comment')
          const header = '# Slither report'
          const body = process.env.REPORT
          await script({ github, context, header, body })

.github/scripts/comment.js:

module.exports = async ({ github, context, header, body }) => {
  const comment = [header, body].join("\n");

  const { data: comments } = await github.rest.issues.listComments({
    owner: context.repo.owner,
    repo: context.repo.repo,
    issue_number: context.payload.number,
  });

  const botComment = comments.find(
    (comment) =>
      // github-actions bot user
      comment.user.id === 41898282 && comment.body.startsWith(header)
  );

  const commentFn = botComment ? "updateComment" : "createComment";

  await github.rest.issues[commentFn]({
    owner: context.repo.owner,
    repo: context.repo.repo,
    body: comment,
    ...(botComment
      ? { comment_id: botComment.id }
      : { issue_number: context.payload.number }),
  });
};

Example workflow: external plugins

The following is a modification of the "simple action" example from earlier. This example uses the slither-plugins property to point to a pip requirements file that gets installed alongside Slither. In this example, the requirements file installs the example plugin provided in the Slither repository, but this can be modified to install extra third-party or in-house detectors.

name: Slither Analysis
on: [push]
jobs:
  analyze:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: crytic/[email protected]
        with:
          target: 'src/'
          slither-plugins: requirements-plugins.txt

requirements-plugins.txt:

slither_my_plugin @ git+https://github.com/crytic/slither#egg=slither_my_plugin&subdirectory=plugin_example