GuardDog is a CLI tool that allows to identify malicious PyPI and npm packages or Go modules. It runs a set of heuristics on the package source code (through Semgrep rules) and on the package metadata.
GuardDog can be used to scan local or remote PyPI and npm packages or Go modules using any of the available heuristics.
pip install guarddogOr use the Docker image:
docker pull ghcr.io/datadog/guarddog
alias guarddog='docker run --rm ghcr.io/datadog/guarddog'Note: On Windows, the only supported installation method is Docker.
# Scan the most recent version of the 'requests' package
guarddog pypi scan requests
# Scan a specific version of the 'requests' package
guarddog pypi scan requests --version 2.28.1
# Scan the 'request' package using 2 specific heuristics
guarddog pypi scan requests --rules exec-base64 --rules code-execution
# Scan the 'requests' package using all rules but one
guarddog pypi scan requests --exclude-rules exec-base64
# Scan a local package archive
guarddog pypi scan /tmp/triage.tar.gz
# Scan a local package directory
guarddog pypi scan /tmp/triage/
# Scan every package referenced in a requirements.txt file of a local folder
guarddog pypi verify workspace/guarddog/requirements.txt
# Scan every package referenced in a requirements.txt file and output a sarif file - works only for verify
guarddog pypi verify --output-format=sarif workspace/guarddog/requirements.txt
# Output JSON to standard output - works for every command
guarddog pypi scan requests --output-format=json
# All the commands also work on npm or go
guarddog npm scan express
# Run in debug mode
guarddog --log-level debug npm scan expressGuardDog comes with 2 types of heuristics:
-
Source code heuristics: Semgrep rules running against the package source code.
-
Package metadata heuristics: Python or Javascript heuristics running against the package metadata on PyPI or npm.
Source code heuristics:
| Heuristic | Description |
|---|---|
| shady-links | Identify when a package contains an URL to a domain with a suspicious extension |
| obfuscation | Identify when a package uses a common obfuscation method often used by malware |
| clipboard-access | Identify when a package reads or write data from the clipboard |
| exfiltrate-sensitive-data | Identify when a package reads and exfiltrates sensitive data from the local system |
| download-executable | Identify when a package downloads and makes executable a remote binary |
| exec-base64 | Identify when a package dynamically executes base64-encoded code |
| silent-process-execution | Identify when a package silently executes an executable |
| dll-hijacking | Identifies when a malicious package manipulates a trusted application into loading a malicious DLL |
| bidirectional-characters | Identify when a package contains bidirectional characters, which can be used to display source code differently than its actual execution. See more at https://trojansource.codes/ |
| steganography | Identify when a package retrieves hidden data from an image and executes it |
| code-execution | Identify when an OS command is executed in the setup.py file |
| cmd-overwrite | Identify when the 'install' command is overwritten in setup.py, indicating a piece of code automatically running when the package is installed |
Metadata heuristics:
| Heuristic | Description |
|---|---|
| empty_information | Identify packages with an empty description field |
| release_zero | Identify packages with an release version that's 0.0 or 0.0.0 |
| typosquatting | Identify packages that are named closely to an highly popular package |
| potentially_compromised_email_domain | Identify when a package maintainer e-mail domain (and therefore package manager account) might have been compromised |
| unclaimed_maintainer_email_domain | Identify when a package maintainer e-mail domain (and therefore npm account) is unclaimed and can be registered by an attacker |
| repository_integrity_mismatch | Identify packages with a linked GitHub repository where the package has extra unexpected files |
| single_python_file | Identify packages that have only a single Python file |
| bundled_binary | Identify packages bundling binaries |
| deceptive_author | This heuristic detects when an author is using a disposable email |
Source code heuristics:
| Heuristic | Description |
|---|---|
| npm-serialize-environment | Identify when a package serializes 'process.env' to exfiltrate environment variables |
| npm-obfuscation | Identify when a package uses a common obfuscation method often used by malware |
| npm-silent-process-execution | Identify when a package silently executes an executable |
| shady-links | Identify when a package contains an URL to a domain with a suspicious extension |
| npm-exec-base64 | Identify when a package dynamically executes code through 'eval' |
| npm-install-script | Identify when a package has a pre or post-install script automatically running commands |
| npm-steganography | Identify when a package retrieves hidden data from an image and executes it |
| bidirectional-characters | Identify when a package contains bidirectional characters, which can be used to display source code differently than its actual execution. See more at https://trojansource.codes/ |
| npm-dll-hijacking | Identifies when a malicious package manipulates a trusted application into loading a malicious DLL |
| npm-exfiltrate-sensitive-data | Identify when a package reads and exfiltrates sensitive data from the local system |
Metadata heuristics:
| Heuristic | Description |
|---|---|
| empty_information | Identify packages with an empty description field |
| release_zero | Identify packages with an release version that's 0.0 or 0.0.0 |
| potentially_compromised_email_domain | Identify when a package maintainer e-mail domain (and therefore package manager account) might have been compromised; note that NPM's API may not provide accurate information regarding the maintainer's email, so this detector may cause false positives for NPM packages. see https://www.theregister.com/2022/05/10/security_npm_email/ |
| unclaimed_maintainer_email_domain | Identify when a package maintainer e-mail domain (and therefore npm account) is unclaimed and can be registered by an attacker; note that NPM's API may not provide accurate information regarding the maintainer's email, so this detector may cause false positives for NPM packages. see https://www.theregister.com/2022/05/10/security_npm_email/ |
| typosquatting | Identify packages that are named closely to an highly popular package |
| direct_url_dependency | Identify packages with direct URL dependencies. Dependencies fetched this way are not immutable and can be used to inject untrusted code or reduce the likelihood of a reproducible install. |
| npm_metadata_mismatch | Identify packages which have mismatches between the npm package manifest and the package info for some critical fields |
| bundled_binary | Identify packages bundling binaries |
| deceptive_author | This heuristic detects when an author is using a disposable email |
Source code heuristics:
| Heuristic | Description |
|---|---|
| shady-links | Identify when a package contains an URL to a domain with a suspicious extension |
Guarddog allows to implement custom sourcecode rules. Sourcecode rules live under the guarddog/analyzer/sourcecode directory, and supported formats are Semgrep or Yara.
- Semgrep rules are language-dependent, and Guarddog will import all
.ymlrules where the language matches the ecosystem selected by the user in CLI. - Yara rules on the other hand are language agnostic, therefore all matching
.yarrules present will be imported.
Is possible then to write your own rule and drop it into that directory, Guarddog will allow you to select it or exclude it as any built-in rule as well as appending the findings to its output.
For example, you can create the following semgrep rule:
rules:
- id: sample-rule
languages:
- python
message: Output message when rule matches
metadata:
description: Description used in the CLI help
patterns:
YOUR RULE HEURISTICS GO HERE
severity: WARNINGThen you'll need to save it as sample-rule.yml and note that the id must match the filename
In the case of Yara, you can create the following rule:
rule sample-rule
{
meta:
description = "Description used in the output message"
target_entity = "file"
strings:
$exec = "exec"
condition:
1 of them
}
Then you'll need to save it as sample-rule.yar.
Note that in both cases, the rule id must match the filename
The easiest way to integrate GuardDog in your CI pipeline is to leverage the SARIF output format, and upload it to GitHub's code scanning feature.
Using this, you get:
- Automated comments to your pull requests based on the GuardDog scan output
- Built-in false positive management directly in the GitHub UI
Sample GitHub Action using GuardDog:
name: GuardDog
on:
push:
branches:
- main
pull_request:
branches:
- main
permissions:
contents: read
jobs:
guarddog:
permissions:
contents: read # for actions/checkout to fetch code
security-events: write # for github/codeql-action/upload-sarif to upload SARIF results
name: Scan dependencies
runs-on: ubuntu-latest
steps:
- uses: actions/checkout@v4
- name: Set up Python
uses: actions/setup-python@v5
with:
python-version: "3.10"
- name: Install GuardDog
run: pip install guarddog
- run: guarddog pypi verify requirements.txt --output-format sarif --exclude-rules repository_integrity_mismatch > guarddog.sarif
- name: Upload SARIF file to GitHub
uses: github/codeql-action/upload-sarif@v3
with:
category: guarddog-builtin
sarif_file: guarddog.sarif- Ensure
>=python3.10is installed - Clone the repository
- Create a virtualenv:
python3 -m venv venv && source venv/bin/activate - Install requirements:
pip install -r requirements.txt - Run GuardDog using
python -m guarddog
- Ensure poetry has an env with
python >=3.10poetry env use 3.10.0 - Install dependencies
poetry install - Run guarddog
poetry run guarddogorpoetry shellthen runguarddog
Running all unit tests: make test
Running unit tests against Semgrep rules: make test-semgrep-rules (tests are here). These use the standard methodology for testing Semgrep rules.
Running unit tests against package metadata heuristics: make test-metadata-rules (tests are here).
You can run GuardDog on legitimate and malicious packages to determine false positives and false negatives. See ./tests/samples
Run the type checker with
mypy --install-types --non-interactive guarddogand the linter with
flake8 guarddog --count --select=E9,F63,F7,F82 --show-source --statistics --exclude tests/analyzer/sourcecode,tests/analyzer/metadata/resources,evaluator/data
flake8 guarddog --count --max-line-length=120 --statistics --exclude tests/analyzer/sourcecode,tests/analyzer/metadata/resources,evaluator/data --ignore=E203,W503Authors:
Inspiration:
- Backstabber’s Knife Collection: A Review of Open Source Software Supply Chain Attacks
- What are Weak Links in the npm Supply Chain?
- A Survey on Common Threats in npm and PyPi Registries
- A Benchmark Comparison of Python Malware Detection Approaches
- Towards Measuring Supply Chain Attacks on Package Managers for Interpreted Languages
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