Software supply chain security is the practice of securing all components involved in developing and deploying a software. The software supply chain includes several elements, ranging from third-party and proprietary code to deployment methods, infrastructures, interfaces, protocols, developer habits, and development tools—and all these need to be safeguarded.
As you’d imagine, the software supply chain makes up a huge part of an organization’s attack surface. Attackers often target weak links in this chain and, in doing so, compromise software providers and their product users.
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We’ll dive deeper into software supply chain security below, including some examples of real-life attacks and security best practices.
What Is the Software Supply Chain?
A software supply chain is the interconnected system of organizations, people, processes, and resources that work together to produce and deliver a piece of software. It includes not only code but also the vast network of information and components surrounding it, including the following:
| Element | Component |
| Developers and development environment | Individual developers: The humans writing the code are part of the chain, as their coding practices, security awareness, and workstation security are crucial. Integrated development environments (IDEs): The tools developers use to write and debug code may have vulnerabilities, or their plugins can be exploited. Source code repositories: Where the source code is stored and managed can be vulnerable to unauthorized access. Compromised repositories can lead to malicious code injection. Local development machines: Developers’ computers, if compromised, can become a point of entry for injecting malicious code into the supply chain. |
| Build systems and infrastructure | Build servers and continuous integration (CI) systems: These systems automate the process of compiling, testing, and packaging software. Compromising them can lead to the automatic distribution of malicious builds. Build scripts and configurations: Malicious modifications to the instructions that define the build process can introduce backdoors or vulnerabilities. Artifact repositories: If compromised, repositories that store built software artifacts (e.g., binaries, libraries, container images) can distribute tainted software. |
| Dependencies and third-party components | Open-source software (OSS) libraries and frameworks: These are prebuilt components used to accelerate development that could contain vulnerabilities that directly impact the security of the final software. Third-party commercial software: The security of proprietary components integrated into the software relies on their vendors’ practices and timely updates. Package managers: Tools used to download and manage dependencies can be compromised and introduce significant risks. |
What Security Risks Are Commonly Found in the Software Supply Chain?
One of the most prevalent software supply chain risks is the presence of vulnerabilities in the proprietary code, third-party libraries, or even the tools used during development. This includes both known vulnerabilities, which are tracked as Common Vulnerabilities and Exposures (CVEs), and unknown vulnerabilities, also known as “zero-day exploits.”
Another significant risk stems from compromised dependencies, which occur when a seemingly trustworthy component, such as an open-source package, is intentionally or unintentionally modified to include malicious code. A notable example is the Copay event-stream attack, where a maintainer added a dependency that was later modified with malicious code, affecting users who updated their packages.
Direct attacks on vendors also pose a threat. By targeting software vendors directly, malicious actors can gain access to their systems and processes, potentially impacting a large number of users. The SolarWinds Orion attack serves as a prime example of this risk. Hackers infiltrated the Orion Platform, a widely used monitoring tool, and distributed a malicious update to numerous organizations.
How to Improve Software Supply Chain Security
Improving software supply chain security requires a multifaceted approach that integrates security practices throughout the entire software life cycle, implementing Software Bills of Materials (SBOMs), automating security tests, and other best practices.
Secure Development Practices
Building a secure software means integrating security into the software development life cycle from its inception. This involves embracing security by design principles—secure coding practices, multifactor authentication (MFA) and other security features, and proactive attack surface reduction, to name a few.
Automated Security Testing Tools
Automating security tests throughout the CI/continuous discovery (CD) pipeline is important for continuous monitoring and early detection of vulnerabilities. Some of the tools that can be integrated for software supply chain security include:
- Static application security testing (SAST) tools: These tools analyze source code for potential vulnerabilities without executing it, allowing developers to identify and fix flaws early in the development cycle.
- Dynamic application security testing (DAST) tools: DAST tools test running applications to identify vulnerabilities from an attacker’s perspective, providing insights into how the application behaves in a runtime environment.
- Software composition analysis (SCA) tools: These systems identify and analyze open-source components and dependencies used in the software, helping detect known vulnerabilities and potential licensing issues associated with third-party components.
Software Bill of Materials
An SBOM is a formal and comprehensive record that lists all the components, dependencies, and metadata associated with a software package. It’s like a list of ingredients for a certain recipe, providing transparency into each block that makes up a software.
The Cybersecurity and Infrastructure Security Agency (CISA) campaigns for the adoption of SBOM, as it can help identify and mitigate known vulnerabilities within software components. When a new vulnerability is discovered in an open-source package, for instance, an organization with a detailed SBOM can quickly assess its exposure and take appropriate action.
Other Software Supply Chain Security Best Practices
Below are some more software supply chain security best practices that don’t fall under the strategies above.
- Using only trusted repositories and verified sources for all software components and dependencies.
- Employing lockfiles or version pinning to ensure that consistent versions of dependencies are used across different environments, reducing the risk of unexpected changes or vulnerabilities that automatic updates may introduce.
- Constantly test and monitor applications for threats even after deployment.
For software users, CISA recommends requiring vendors to provide SBOM and guidance on how to verify the integrity of different components. Customers are also encouraged to draft contractual agreements to enable improved software supply chain security controls and mitigations.
Key Takeaways
- Software supply chain security is the practice of securing all components involved in developing and deploying a software.
- The software supply chain includes elements like third-party and proprietary code, deployment methods, infrastructures, and developer habits, all of which need to be secured.
- The software supply chain is a significant part of an organization’s attack surface.
- Common security risks include vulnerabilities in code or tools, compromised dependencies, and direct attacks on vendors.
- Improving software supply chain security requires a comprehensive approach, including secure development practices, automated security testing tools, SBOMs, and using trusted repositories.
Sources
- https://cycode.com/blog/what-is-a-software-supply-chain/
- https://owasp.org/www-community/Source_Code_Analysis_Tools
- https://www.cisa.gov/sites/default/files/2023-01/ESF_SECURING_THE_SOFTWARE_SUPPLY_CHAIN_CUSTOMER.PDF
- https://www.cisa.gov/resources-tools/resources/securing-software-supply-chain-recommended-practices-guide-customers-and
