Introduction

dep-scan is a fully open-source security audit tool based on known vulnerabilities, advisories, and license limitations for project dependencies. Both local repositories and container images are supported as the input, and the tool is ideal for CI environments with built-in build-breaker logic.

Features

• Scan most application code - local repos, Linux container images, Kubernetes manifests, and OS - to identify known CVEs with prioritization
• Package vulnerability scanning is performed locally and is quite fast. No server is used!
• Generate Software Bill-of-Materials (SBoM) with Vulnerability Exploitability Exchange (VEX) information
• Perform deep packages risk audit for dependency confusion attacks and maintenance risks (See risk audit)

Vulnerability Data sources

• OSV
• NVD
• GitHub
• NPM
• Linux vuln-list (Use --cache-os)

Linux distros

• AlmaLinux
• Debian
• Alpine
• Amazon Linux
• Arch Linux
• RHEL/CentOS
• Rocky Linux
• Ubuntu
• OpenSUSE/SLES
• Photon

Application vulnerabilities would be reported for all Linux distros and Windows. To download the full vulnerability database suitable for scanning OS, invoke dep-scan with --cache-os for the first time. dep-scan would also download the appropriate database based on project type automatically.

Usage

dep-scan is ideal for use during continuous integration (CI) and as a local development tool.

OCI Artifacts via ORAS cli

Use ORAS cli to download the dep-scan binary and the vulnerability database for effortless integration. Example workflow is here.

export VDB_HOME=depscan
mkdir -p $VDB_HOME
oras pull ghcr.io/appthreat/vdb:v5 -o $VDB_HOME
oras pull ghcr.io/appthreat/depscan:v4 -o $VDB_HOME

Single binary executables

Download the executable binary for your operating system from the releases page. These binary bundle the following:

• dep-scan with Python 3.10
• cdxgen with Node.js 18
• cdxgen binary plugins

curl -LO https://github.com/appthreat/depscan-bin/releases/download/v3.5.1/depscan-linux-amd64
chmod +x depscan-linux-amd64
./depscan-linux-amd64 --help

On Windows,

curl -LO https://github.com/appthreat/depscan-bin/releases/download/v3.5.1/depscan.exe
.\depscan.exe --help

Server mode

dep-scan and cdxgen could be run in server mode. Use the included docker compose file to get started.

git clone https://github.com/AppThreat/dep-scan
docker compose up

depscan --server --server-host 0.0.0.0 --server-port 7070

In server mode, use /cache endpoint to cache the vulnerability database.

# This would take over 5 minutes
curl http://0.0.0.0:7070/cache

Cache all vulnerabilities including os.

# This would take over 5 minutes
curl http://0.0.0.0:7070/cache?os=true

Use the /scan endpoint to perform scans.

curl --json '{"path": "/tmp/vulnerable-aws-koa-app", "type": "js"}' http://0.0.0.0:7070/scan

curl --json '{"url": "https://github.com/HooliCorp/vulnerable-aws-koa-app", "type": "js"}' http://0.0.0.0:7070/scan -o app.vex.json

Use with ShiftLeft Scan

dep-scan is integrated with scan, a free and open-source SAST tool. To enable this feature simply pass depscan to the --type argument. Refer to the scan documentation for more information.

---
--type python,depscan,credscan

This approach should work for all CI environments supported by scan.

Scanning projects locally (Python version)

sudo npm install -g @cyclonedx/cdxgen
pip install appthreat-depscan

This would install two commands called cdxgen and scan.

You can invoke the scan command directly with the various options.

cd <project to scan>
depscan --src $PWD --reports-dir $PWD/reports

Full list of options are below:

usage: depscan [-h] [--no-banner] [--cache] [--cache-os] [--sync] [--suggest] [--risk-audit] [--private-ns PRIVATE_NS] [-t PROJECT_TYPE] [--bom BOM] -i SRC_DIR
              [--reports-dir REPORTS_DIR] [--no-error] [--deep]
  -h, --help            show this help message and exit
  --no-banner           Do not display banner
  --cache               Cache vulnerability information in platform specific user_data_dir
  --cache-os            Cache OS vulnerability information in platform specific user_data_dir
  --sync                Sync to receive the latest vulnerability data. Should have invoked cache first.
  --risk-audit          Perform package risk audit (slow operation). Npm only.
  --private-ns PRIVATE_NS
                        Private namespace to use while performing oss risk audit. Private packages should not be available in public registries by default. Comma
                        separated values accepted.
  -t PROJECT_TYPE, --type PROJECT_TYPE
                        Override project type if auto-detection is incorrect
  --bom BOM             Examine using the given Software Bill-of-Materials (SBoM) file in CycloneDX format. Use cdxgen command to produce one.
  -i SRC_DIR, --src SRC_DIR
                        Source directory
  --reports-dir REPORTS_DIR
                        Reports directory
  --no-error            Continue on error to prevent build from breaking
  --deep                Perform deep scan by passing this --deep argument to cdxgen. Useful while scanning docker images and OS packages.
  --no-universal        Depscan would attempt to perform a single universal scan instead of individual scans per language type.
  --no-vuln-table       Do not print the table with the full list of vulnerabilities. This can help reduce console output.
  --threatdb-server THREATDB_SERVER
                        ThreatDB server url. Eg: https://api.sbom.cx
  --threatdb-username THREATDB_USERNAME
                        ThreatDB username
  --threatdb-password THREATDB_PASSWORD
                        ThreatDB password
  --threatdb-token THREATDB_TOKEN
                        ThreatDB token for token based submission
  --privado-json PRIVADO_JSON
                        Enrich the VEX report with information from privado.ai json report.

Scanning containers locally (Python version)

Scan latest tag of the container shiftleft/scan-slim

depscan --no-error --cache --src shiftleft/scan-slim -o containertests/depscan-scan.json -t docker

Include license to the type to perform license audit.

depscan --no-error --cache --src shiftleft/scan-slim -o containertests/depscan-scan.json -t docker,license

You can also specify the image using the sha256 digest

depscan --no-error --src redmine@sha256:a5c5f8a64a0d9a436a0a6941bc3fb156be0c89996add834fe33b66ebeed2439e -o containertests/depscan-redmine.json -t docker

You can also save container images using docker or podman save command and pass the archive to depscan for scanning.

docker save -o /tmp/scanslim.tar shiftleft/scan-slim:latest
# podman save --format oci-archive -o /tmp/scanslim.tar shiftleft/scan-slim:latest
depscan --no-error --src /tmp/scanslim.tar -o reports/depscan-scan.json -t docker

Refer to the docker tests under GitHub action workflow for this repo for more examples.

Scanning projects locally (Docker container)

ghcr.io/appthreat/dep-scan or public.ecr.aws/appthreat/dep-scan:latest container image can be used to perform the scan.

To scan with default settings

docker run --rm -v $PWD:/app ghcr.io/appthreat/dep-scan scan --src /app --reports-dir /app/reports

Using AWS public ECR image

docker run --rm -v $PWD:/app public.ecr.aws/appthreat/dep-scan scan --src /app --reports-dir /app/reports

To scan with custom environment variables based configuration

docker run --rm \
    -e VDB_HOME=/db \
    -e NVD_START_YEAR=2010 \
    -e GITHUB_PAGE_COUNT=5 \
    -e GITHUB_TOKEN=<token> \
    -v /tmp:/db \
    -v $PWD:/app ghcr.io/appthreat/dep-scan scan --src /app --reports-dir /app/reports

In the above example, /tmp is mounted as /db into the container. This directory is then specified as VDB_HOME for caching the vulnerability information. This way the database can be cached and reused to improve performance.

Supported languages and package format

dep-scan uses cdxgen command internally to create Software Bill-of-Materials (SBoM) file for the project. This is then used for performing the scans.

The following projects and package-dependency format is supported by cdxgen.

NOTE

The docker image for dep-scan currently doesn't bundle suitable java and maven commands required for bom generation. To workaround this limitation, you can -

1. Use python-based execution from a VM containing the correct versions for java, maven and gradle.
2. Generate the bom file by invoking cdxgen command locally and subsequently passing this to dep-scan via the --bom argument.

Integration with CI environments

Integration with Azure DevOps

Refer to this example yaml configuration for integrating dep-scan with Azure Pipelines. The build step would perform the scan and display the report inline as shown below:

Integration with GitHub Actions

This tool can be used with GitHub Actions using this action.

This repo self-tests itself with both sast-scan and dep-scan! Check the GitHub workflow file of this repo.

- name: Self dep-scan
  uses: AppThreat/dep-scan-action@master
  env:
    VDB_HOME: ${{ github.workspace }}/db
    GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

Customization through environment variables

The following environment variables can be used to customise the behaviour.

• VDB_HOME - Directory to use for caching database. For docker based execution, this directory should get mounted as a volume from the host
• NVD_START_YEAR - Default: 2018. Supports upto 2002
• GITHUB_PAGE_COUNT - Default: 2. Supports upto 20

GitHub Security Advisory

To download security advisories from GitHub, a personal access token with the following scope is necessary.

• read:packages

export GITHUB_TOKEN="<PAT token>"

Suggest mode

Fix version for each vulnerability is retrieved from the sources. Sometimes, there might be known vulnerabilities in the fix version reported. Eg: in the below screenshot the fix versions suggested for jackson-databind might contain known vulnerabilities.

By passing an argument --suggest it is possible to force depscan to recheck the fix suggestions. This way the suggestion becomes more optimal for a given package group.

Notice, how the new suggested version is 2.9.10.5 which is an optimal fix version. Please note that the optimal fix version may not be the appropriate version for your application based on compatibility.

Package Risk audit

--risk-audit argument enables package risk audit. Currently, only npm and pypi packages are supported in this mode. A number of risk factors are identified and assigned weights to compute a final risk score. Packages that then exceed a maximum risk score (config.pkg_max_risk_score) are presented in a table.

Use --private-ns to specify the private package namespace that should be checked for dependency confusion type issues where a private package is available on public npm/pypi registry.

For example, to check if private packages with namespaces @appthreat and @shiftleft are not accidentally made public, use the below argument.

--private-ns appthreat,shiftleft

Refer to pkg_query.py::get_category_score method for the risk formula.

Automatic adjustment

A parameter called created_now_quarantine_seconds is used to identify packages that are safely past the quarantine period (1 year). Certain risks such as pkg_min_versions and pkg_min_maintainers are suppressed for packages past the quarantine period. This adjustment helps reduce noise since it is unlikely that a malicious package can exist in a registry unnoticed for over a year.

Configuring weights

All parameters can be customized by using environment variables. For eg:

export PKG_MIN_VERSIONS=4 to increase and set the minimum versions category to 4.

Live OS scan

By passing -t os, depscan can generate an SBoM for a live operating system or a VM with OS packages and kernel information. Optionally, pass the argument --deep to generate an SBoM with both OS and application packages and to check for application vulnerabilities.

All OS packages.

depscan -t os -i . -o reports/depscan.json

All OS and application packages.

depscan -t os --deep -i . -o reports/depscan.json

License scan

dep-scan can scan the dependencies for any license limitations and report them directly on the console log. To enable license scanning set the environment variable FETCH_LICENSE to true.

export FETCH_LICENSE=true

The license data is sourced from choosealicense.com and is quite limited. If the license of a given package cannot be reliably matched against this list it will get silently ignored to reduce any noise. This behavior could change in the future once the detection logic gets improved.

Kubernetes and Cloud apps

dep-scan could auto-detect most cloud applications and Kubernetes manifest files. Pass the argument -t yaml-manifest to manually specify the type.

Alternatives

Dependency Check is considered the industry standard for open-source dependency scanning. After personally using this great product for many years, I decided to write my own from scratch, partly as a dedication to this project. By using a streaming database based on msgpack and using JSON schema, dep-scan is more performant than dependency check in CI environments. Plus, with support for GitHub advisory source and grafeas report export and submission, dep-scan is on track to become a next-generation dependency audit tool.

Several other tools piggyback on Sonatype ossindex API server. For some reason, I always felt uncomfortable letting a commercial company track the usage of various projects worldwide. dep-scan is, therefore, 100% private and guarantees never to perform any tracking!

Trivy, grype etc

These mature projects are considered the benchmark for container, filesystem and registry scanning. dep-scan is yet to be benchmarked against these projects for results and performance. dep-scan even uses Trivy for container SBoM generation via cdxgen-binary-plugins, although this would change in the future. I aspire to make dep-scan outperform these projects with simplicity and actionable results. The CVE insights offered by dep-scan could be used for prioritization to reduce the number of package updates and container rebuilds.

Discord support

The developers could be reached via the discord channel.