Package Manager Guard (PMG)

PMG protects developers from getting compromised by malicious packages.
See example

Key Features

• Wraps your favorite package manager (eg. npm, pnpm, pip and more)
• Blocks malicious packages at install time
• No configuration required, just install and use
• Maintains package installation event log for transparency and audit trail
• Enforces least privilege and defense in depth using OS native sandboxing

PMG guarantees its own artifact integrity using GitHub and npm attestations. Users can cryptographically prove that the binary they run matches the source code they reviewed, eliminating the risk of tampered or malicious builds. See why and how to trust PMG.

Quick Start

Install pmg using your favorite package manager:

# MacOS/Linux with Homebrew
brew install safedep/tap/pmg

# Other platforms
npm install -g @safedep/pmg

Note: More installation options are available. See why and how to trust PMG.

Set up pmg to protect your development environment from malicious packages:

pmg setup install

Note: Make sure to restart your terminal or source your shell's config file.

Continue using your favorite package manager as usual:

npm install <package-name>

uv pip install <package-name>

Features

• Malicious package identification using SafeDep Cloud with realtime threat detection
• Deep dependency analysis and transitive dependency resolution
• Fast and efficient package verification
• Defense in depth using OS native sandboxing
• Seamless integration with existing package managers
• Automated shell integration with cross-shell support
• Package installation tracking and event logging

Supported Package Managers

PMG supports the following package managers:

Package Manager	Status	Command
npm	✅	pmg npm install <package>
pnpm	✅	pmg pnpm add <package>
bun	✅	pmg bun add <package>
yarn	✅	pmg yarn add <package>
pip	✅	pmg pip install <package>
uv	✅	pmg uv add <package> or pmg uv pip install <package>
poetry	✅	pmg poetry add <package>
npx	✅	pmg npx <package> <action>
pnpx	✅	pmg pnpx <package> <action>

Want us to support your favorite package manager? Open an issue and let us know!

Installation

Homebrew

You can install pmg using homebrew in MacOS and Linux

brew tap safedep/tap
brew install safedep/tap/pmg

Binaries

Download the latest binary from the releases page.

Build from Source

Ensure $(go env GOPATH)/bin is in your $PATH

go install github.com/safedep/pmg@latest

Setup

PMG provides built-in commands to automatically configure shell aliases for seamless integration:

Install Aliases

Set up PMG to intercept package manager commands:

pmg setup install

Custom config directory

PMG_CONFIG_DIR=/path/to/config pmg setup install

The setup command will:

• Create a ~/.pmg.rc file containing package manager aliases
• Automatically add a source line to your shell configuration files
• Create a default config file. See config template

Note

: After running pmg setup install, restart your terminal or run source ~/.zshrc (or your shell's config file) to activate the aliases.

Remove Aliases

To remove PMG aliases and restore original package manager behavior:

pmg setup remove

This will:

• Remove the source line from your shell configuration files
• Delete the ~/.pmg.rc file

⚠️ Note: Aliases might still be active in your current terminal session. Restart your terminal or use unalias <cmd> to remove them instantly.

Usage

Active Scanning

Use the --paranoid flag to perform active malware scanning on unknown packages (requires SafeDep Cloud credentials):

pmg --paranoid npm install <package-name>

Silent Mode

Use the --silent flag to run PMG in silent mode:

pmg --silent npm install <package-name>

Dry Run

Use the --dry-run flag to skip actual package installation. When enabled pmg will not execute package manager commands. Useful for checking packages and their transitive dependencies for malware.

pmg --dry-run npm install <package-name>

Verbose Mode

Use the --verbose flag to run PMG in verbose mode:

pmg --verbose npm install <package-name>

Debugging

Use the --debug flag to enable debug mode:

pmg --debug npm install <package-name>

Store the debug logs in a file:

pmg --debug --log /tmp/debug.json npm install <package-name>

Insecure Installation

Allows bypassing the blocking behavior when malicious packages are detected during installation.

⚠️ Warning: This is a security feature bypass. Use with extreme caution and only when you understand the risks.

export PMG_INSECURE_INSTALLATION=true
pmg npm install <package-name>

Advanced

• Trusted Packages
• Proxy Mode
• Sandbox

Contributing

Refer to CONTRIBUTING.md

Limitations

Private package artifacts inaccessible in non-proxy mode

If pmg cannot retrieve private package artifacts (such as files or metadata), it cannot perform dependency tree analysis. This is a limitation of non-proxy mode, where pmg is responsible for resolving dependencies and is unable to resolve transitive dependencies for private (inaccessible) packages.

This limitation does not apply when Proxy Mode is enabled.

Approximate dependency version resolution

pmg resolves the transitive dependencies of a package to be installed. It does it by querying package registry APIs such as npmjs and pypi. However, almost always, dependency versions are specified as ranges instead of specific version. Different package managers have different ways of resolving these ranges. It also depends on peer or host dependencies already available in the application.

pmg is required to block a malicious package before it is installed. Hence it applies its own heuristic to choose a version from a version range for evaluation. This is fine when all versions of a given package is malicious. However, there is a possibility of inconsistency when a specific version of a package is malicious.

PyPI registry scanning only

pmg only scans packages available in the PyPI registry when using any python package manager. Packages installed from alternative sources such as Git URLs, local file paths, or private registries are not analyzed for malware detection. This limitation applies to direct installations and transitive dependencies sourced from non-PyPI locations.

Telemetry

pmg collects anonymous telemetry to help us understand how it is used and improve the product. To disable telemetry, set PMG_DISABLE_TELEMETRY environment variable to true.

export PMG_DISABLE_TELEMETRY=true