Software Supply Chain Security Notes¶

A comprehensive resource on Software Supply Chain Security. This site contains notes, guides, and best practices for securing your software supply chain.

What is Software Supply Chain Security?¶

Software supply chain security focuses on protecting the integrity, quality, and trustworthiness of software throughout its development lifecycle -- from code creation to deployment and beyond. It encompasses all the components, processes, and systems that go into building and delivering software.

Recent high-profile incidents like SolarWinds and Log4j vulnerabilities have highlighted the critical importance of securing every link in the software supply chain. Organizations are now recognizing that traditional security approaches focusing solely on perimeter defense are insufficient. Modern security requires a holistic approach that secures the entire software development lifecycle.

The Evolution of Supply Chain Security¶

Software supply chain security has evolved dramatically over the past decade:

Organizations must adapt to this evolving landscape by implementing comprehensive security controls across their entire software development and deployment pipeline.

Supply Chain Visualization¶

The software supply chain is a complex ecosystem involving multiple components and security controls. The diagram below illustrates the core flow and critical security measures:

---
id: 95d0de52-7ffc-4e84-8829-2e5903df6ea6
---
flowchart LR
    classDef vulnerable fill:#f96, stroke:#333, stroke-width:2px
    classDef secure fill:#6f6, stroke:#333, stroke-width:2px
    classDef standard fill:#69f, stroke:#333, stroke-width:2px, color:white
    classDef attack fill:#f66, stroke:#900, stroke-width:2px, color:white, stroke-dasharray: 5 5

    A[Source Code\nRepository] --> B[Dependencies\nManagement]
    B --> C[Build\nProcess]
    C --> D[Artifacts\nRepository]
    D --> E[Distribution\nPipeline]
    E --> F[Production\nDeployment]

    G[Vulnerability\nScanning] -.-> A
    H[SBOM\nGeneration] -.-> B
    I[Signed\nCommits] -.-> A
    J[CI/CD\nSecurity] -.-> C
    K[Code\nSigning] -.-> D
    L[Attestations] -.-> D
    M[Dependency\nPinning] -.-> B
    N[Reproducible\nBuilds] -.-> C
    O[Integrity\nVerification] -.-> E
    P[Runtime\nMonitoring] -.-> F

    X[Compromised\nDependency] -. Attack Vector .-> B
    Y[Build Server\nCompromise] -. Attack Vector .-> C
    Z[Artifact\nTampering] -. Attack Vector .-> E

    class A,B,C,D,E,F standard
    class G,H,I,J,K,L,M,N,O,P secure
    class X,Y,Z attack

    click A href "#source-code-protection" "Learn about Source Code Protection"
    click B href "#dependency-management" "Learn about Dependency Management"
    click C href "#secure-build-processes" "Learn about Secure Build Processes"
    click D href "#artifact-protection" "Learn about Artifact Protection"
    click E href "#secure-distribution" "Learn about Secure Distribution"
    click F href "#secure-deployment" "Learn about Secure Deployment"

Understanding the Supply Chain Flow¶

1. Development Phase: Developers write code and submit it to source repositories
2. Dependency Phase: Dependencies are integrated from various sources
3. Build Phase: Automated processes compile and package the software
4. Artifact Phase: Built artifacts are stored in repositories
5. Distribution Phase: Artifacts are distributed to end users or deployment targets
6. Deployment Phase: Software is deployed to production environments

Each phase has unique security requirements and potential vulnerabilities that must be addressed with specific security controls.

Common Attack Vectors¶

The red dashed lines in the diagram highlight common attack vectors:

• Compromised Dependencies: Attackers inject malicious code into third-party libraries
• Build Server Compromises: CI/CD environments are targeted to inject malware during builds
• Artifact Tampering: Built artifacts are modified before or during distribution

These attack methods have been employed in several high-profile supply chain attacks.

Key Components of Software Supply Chain Security¶

1. Source Code Protection
2. Access controls
3. Code review

4. Vulnerability scanning

5. Dependency Management

6. Vulnerability scanning
7. Software Bill of Materials (SBOM)

8. Dependency pinning

9. Secure Build Processes

10. Isolated build environments
11. Reproducible builds

12. Pipeline security

13. Artifact Protection

14. Code signing
15. Provenance

16. Attestations

17. Secure Deployment

18. Deployment validation
19. Runtime verification
20. Monitoring

Recent Major Supply Chain Attacks¶

Getting Started¶

To begin securing your software supply chain, start with these essential steps:

1. Understand Package Ecosystem Risks: Review Package Ecosystem Security to understand the specific vulnerabilities in npm, PyPI, Maven, and other ecosystems
2. Create an Inventory: Generate a Software Bill of Materials (SBOM)
3. Implement Dependency Security: Follow dependency management practices
4. Secure Your Pipeline: Protect your CI/CD pipeline
5. Adopt Standards: Learn about the SLSA Framework