---
title: "Software Supply Chain Security"
description: "A comprehensive guide to securing the software supply chain using open source tools and standards"
keywords: ["software supply chain", "security", "SBOM", "vulnerability scanning", "Sigstore", "SLSA", "in-toto", "dependency confusion"]
category: "security"
---

The security of the software supply chain has become a critical concern in recent years, as high-profile attacks like the SolarWinds breach have highlighted the need for robust measures to ensure the integrity and provenance of the software we rely on. Fortunately, there are a number of open source tools and standards that can help organizations address these challenges.

One such tool is Syft, a software bill of materials (SBOM) generation tool from the Anchore project. Syft version 0.53.0 can analyze container images, file trees, and other software artifacts to produce detailed SBOMs that capture information about the components, licenses, and vulnerabilities present. These SBOMs can then be used to identify and mitigate supply chain risks.

Complementing Syft is Grype, a vulnerability scanning tool that can be used to assess the security posture of software artifacts. Grype version 0.43.0 can integrate with Syft-generated SBOMs to provide a comprehensive view of the vulnerabilities present in a software supply chain, allowing organizations to prioritize and address them effectively.

Another important piece of the supply chain security puzzle is Sigstore, a project that provides a set of open source tools for signing, verifying, and protecting software artifacts. Cosign, a Sigstore component, allows developers to cryptographically sign container images, code repositories, and other artifacts, providing a way to verify their provenance and integrity.

The SLSA (Supply Chain Levels for Software Artifacts) framework is a set of security controls and best practices for securing the software supply chain. SLSA defines four levels of security, with each level building upon the previous one. By aligning their processes and tooling with the SLSA framework, organizations can ensure that their software supply chain meets a consistent, verifiable standard of security.

In-toto is another important tool for supply chain security, providing a way to create and verify "attestations" about the various steps involved in building and deploying software. These attestations can be used to establish a verifiable chain of custody, helping to detect and prevent supply chain attacks like dependency confusion.

Dependency confusion attacks, where a malicious actor publishes a package with the same name as a legitimate dependency, can be a significant risk in the software supply chain. Tools like Dependabot and Renovate can help mitigate this risk by automatically monitoring and updating dependencies, ensuring that the latest, secure versions are used.

Finally, the practice of reproducible builds is an important technique for ensuring the integrity of software artifacts. By ensuring that a given build process always produces the same output, regardless of the build environment, organizations can have greater confidence that the software they're using is exactly what the developers intended.Provenance verification is a critical component of securing the software supply chain, as it allows organizations to trace the origin and history of software artifacts. Tools like in-toto can be used to create and verify provenance information, capturing details about the various steps involved in the software development and deployment process. This provenance data can then be used to detect and prevent supply chain attacks, as well as to ensure compliance with industry standards and regulatory requirements.

Another important consideration in software supply chain security is the use of trusted, verified software components. The SLSA framework, mentioned earlier, provides guidance on how to ensure that the software used in a supply chain is trustworthy, with each level of the framework introducing additional security controls and best practices. For example, SLSA Level 3 requires the use of reproducible builds, which ensure that a given build process always produces the same output, regardless of the build environment.

Reproducible builds are a powerful technique for ensuring the integrity of software artifacts, as they allow organizations to verify that the software they're using is exactly what the developers intended. By comparing the output of a build process to a known, trusted reference, organizations can detect any unauthorized changes or tampering. This is particularly important in the context of the software supply chain, where software artifacts may pass through multiple stages and environments before reaching the end user.

In addition to the tools and techniques discussed so far, organizations should also consider the use of automated dependency management solutions, such as Dependabot and Renovate. These tools can continuously monitor the dependencies used in a software project, automatically updating them to the latest, most secure versions. This helps to mitigate the risk of dependency confusion attacks, where a malicious actor publishes a package with the same name as a legitimate dependency, potentially compromising the software supply chain.

Overall, securing the software supply chain requires a multi-faceted approach, leveraging a combination of tools, standards, and best practices. By implementing solutions like Syft, Grype, Sigstore, SLSA, in-toto, and reproducible builds, organizations can significantly reduce the risk of supply chain attacks and ensure the integrity and provenance of the software they use and distribute.Another important aspect of software supply chain security is the use of in-toto attestations. In-toto is an open source framework that allows developers to create and verify "attestations" about the various steps involved in the software development and deployment process. These attestations can capture information about who performed a particular step, what inputs were used, and what the expected outputs should be. By verifying these attestations, organizations can establish a verifiable chain of custody, helping to detect and prevent supply chain attacks.

The SLSA framework, which we discussed earlier, also includes specific requirements around in-toto attestations. For example, SLSA Level 4, the highest level of the framework, mandates the use of in-toto attestations to capture provenance information about the software build and deployment process. This ensures that the entire supply chain, from source code to final artifact, is subject to rigorous security controls and verification.

In addition to in-toto, the SLSA framework also emphasizes the importance of reproducible builds, which we touched on earlier. Reproducible builds are a technique that ensures a given build process always produces the same output, regardless of the build environment. This is crucial for verifying the integrity of software artifacts, as it allows organizations to compare the output of a build process to a known, trusted reference.

Dependency confusion attacks, where a malicious actor publishes a package with the same name as a legitimate dependency, are another significant risk in the software supply chain. To mitigate this risk, organizations should consider the use of automated dependency management solutions, such as Dependabot and Renovate. These tools continuously monitor the dependencies used in a software project, automatically updating them to the latest, most secure versions, reducing the likelihood of a successful dependency confusion attack.

Finally, it's worth noting that securing the software supply chain is an ongoing process that requires vigilance and continuous improvement. As new threats and attack vectors emerge, organizations must stay informed and be prepared to adapt their security measures accordingly. By leveraging the tools and techniques discussed in this document, and staying up-to-date with the latest industry best practices, organizations can significantly enhance the security and integrity of their software supply chain.Another important tool in the software supply chain security arsenal is Sigstore, a project that provides a set of open source tools for signing, verifying, and protecting software artifacts. Sigstore's Cosign component, in particular, allows developers to cryptographically sign container images, code repositories, and other artifacts, providing a way to verify their provenance and integrity. By using Cosign, organizations can ensure that the software they're using or distributing has been signed by a trusted party, reducing the risk of supply chain attacks.

The SLSA framework, which we've discussed previously, also includes specific requirements around Sigstore and other signing and verification mechanisms. For example, SLSA Level 3 mandates the use of signed artifacts, ensuring that all software components in the supply chain have been cryptographically verified. By aligning their processes and tooling with the SLSA framework, organizations can be confident that their software supply chain meets a consistent, verifiable standard of security.

Dependency management is another critical aspect of software supply chain security, and tools like Dependabot and Renovate can play a key role in mitigating the risks associated with dependency confusion attacks. These tools continuously monitor the dependencies used in a software project, automatically updating them to the latest, most secure versions. This helps to reduce the likelihood of a successful dependency confusion attack, where a malicious actor publishes a package with the same name as a legitimate dependency, potentially compromising the software supply chain.

In addition to the tools and techniques we've discussed, the software supply chain security landscape is also shaped by the emergence of new standards and frameworks, such as the in-toto attestation system. In-toto allows developers to create and verify "attestations" about the various steps involved in the software development and deployment process, capturing information about who performed a particular step, what inputs were used, and what the expected outputs should be. By verifying these attestations, organizations can establish a verifiable chain of custody, helping to detect and prevent supply chain attacks.

As the software supply chain becomes an increasingly critical and complex part of the modern technology landscape, the need for robust security measures has never been more pressing. By leveraging the tools and techniques discussed in this document, including Syft, Grype, Sigstore, SLSA, in-toto, and automated dependency management solutions, organizations can significantly enhance the security and integrity of their software supply chain, reducing the risk of costly and damaging attacks.