# Security Scanner API

Bun's package manager can scan packages before installing them, to catch supply chain attacks and known vulnerabilities.

---

## Quick Start

Configure a security scanner in your `bunfig.toml`:

```toml bunfig.toml icon="settings"
[install.security]
scanner = "@oven/bun-security-scanner" # example name, replace with your scanner's package
```

With a scanner configured, Bun:

- Scans all packages before installation
- Displays security warnings and advisories
- Cancels installation if the scanner finds fatal advisories

---

## How It Works

Security scanners analyze packages during `bun install`, `bun add`, and other package operations. They can detect:

- Known security vulnerabilities (CVEs)
- Malicious packages
- License compliance issues

### Security Levels

Scanners report issues at two severity levels:

- **`fatal`** - Installation stops immediately, exits with non-zero code
- **`warn`** - In interactive terminals, prompts to continue; in CI, exits immediately

---

## Using Pre-built Scanners

Security companies publish Bun security scanners as npm packages.

### Installing a Scanner

Install a security scanner from npm:

```bash terminal icon="terminal"
bun add -d @oven/bun-security-scanner
```

<Note>
  `@oven/bun-security-scanner` is an example package name, not a real package. Replace it with the scanner you want to
  use, and consult that scanner's documentation for the exact package name and installation instructions. You install
  most scanners with `bun add`.
</Note>

### Configuring the Scanner

After installation, configure it in your `bunfig.toml`:

```toml bunfig.toml icon="settings"
[install.security]
scanner = "@oven/bun-security-scanner" # example name, replace with your scanner's package
```

### Enterprise Configuration

Some enterprise scanners take authentication and other configuration from environment variables:

```bash terminal icon="terminal"
# This might go in ~/.bashrc, for example
export SECURITY_API_KEY="your-api-key"

# The scanner will now use these credentials automatically
bun install
```

Consult your scanner's documentation for which environment variables to set and any other required configuration.

### Authoring your own scanner

For a complete example with tests and CI setup, see the official template:
[github.com/oven-sh/security-scanner-template](https://github.com/oven-sh/security-scanner-template)

## Related

- [Configuration (bunfig.toml)](/runtime/bunfig#install-security-scanner)
- [Package Manager](/pm/cli/install)
- [Security Scanner Template](https://github.com/oven-sh/security-scanner-template)