Appsec Knowledge Center

Understanding Software Bill Of Materials (SBOM): A Keystone In Modern Application Security And Compliance

5 min.

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A Software Bill of Materials (SBOM) provides comprehensive visibility into the components within an organization’s software supply chain. This insight helps teams identify security risks within their supply chains and determine quickly whether newly disclosed vulnerabilities impact any software they depend on.

When developers build modern applications, they often rely heavily on third-party resources. They might integrate open source packages or libraries into an app, for example, or configure dependencies that the application automatically installs when it runs. These and any other resources that factor into the application form its software supply chain.

Because vulnerabilities that impact any components within an app’s software supply chain could potentially place the app itself at risk, maintaining visibility into supply chains is crucial. Simply put, if an organization lacks a comprehensive list of all software resources that an application uses or depends on, it lacks an efficient way of knowing whether any security issues affect the supply chain.

Software Bill of Materials (SBOM) plays a central role in delivering this visibility into software components and enabling effective software supply chain risk management.

Keep reading for a dive into what an SBOM is, why SBOMs are important in supply chain and application security, and how teams can use SBOMs in the event of a security breach.

What Is An SBOM?

An SBOM is a detailed inventory of all of the components within a software product. In addition to listing the components themselves, SBOMs typically also include information such as which versions of a given library or module an application uses, such as where the component originated, and which software licensing terms govern it.

SBOMs are usually produced by supply chain security software using a standardized structure, such as CycloneDX or SPDX.

SBOM And Application Security

Using this data, developers and security analysts can determine quickly whether any part of their supply chains are at risk. For example, if a security advisory appears for a certain version of an open source library, an organization can refer to its SBOMs to check whether any of its apps use the vulnerable library. If so, it will know that it needs to remediate the vulnerability to ensure that it doesn’t become a vector for attack.

The ability to identify vulnerable components quickly with the help of an SBOM is invaluable because it reduces the time that an app is subject to potential breaches. Exploits against zero-day vulnerabilities typically begin as soon as the vulnerabilities are announced, so the faster an organization can find and fix vulnerable apps, the lower its risk of suffering a breach.

SBOMs can also aid in regulatory compliance by ensuring that applications adhere to security standards and guidelines. By demonstrating that it generates and uses SBOMs, an organization can help to prove to regulators that it follows cyber hygiene best practices.

SBOM In Software Supply Chain Security

In addition to helping to protect individual applications, SBOMs play an important role in keeping overall software supply chains secure.

It’s common for supply chains to overlap, meaning that some components are used to build multiple apps. For example, popular open source libraries, like libc, could be in use within dozens or hundreds of apps deployed by a single organization.

By helping to identify instances when those components become vulnerable to attack, SBOMs empower developers and security analysts to assess the overall safety of their software ecosystems. If vulnerabilities within a widely used library or other resource frequently recur, for instance, they might decide to modify their supply chains by switching to an alternative component with a stronger security track record.

The Role Of SBOMs In CI/CD Processes

Generating an SBOM with the help of software supply chain security tools is important no matter how developers build apps. However, SBOMs are especially critical for organizations that use Continuous Integration/Continuous Delivery (CI/CD). CI/CD, a common practice among DevOps and DevSecOps teams today, involves making changes to application codebases on a frequent, ongoing basis.

When code changes constantly, teams must also constantly track changes to their supply chains. If developers add a new module to an app to build a new feature, for instance, they should record that change in the app’s SBOM so the SBOM data remains up-to-date.

The best way to do this is to integrate SBOM generation automatically into CI/CD workflows, ensuring that every application release is accompanied by an accurate inventory of its supply chain.

By automating SBOM generation as part of CI/CD, teams not only save time and reduce the risk of oversights (like forgetting to record a change to a module or library version), but also make it easier to audit supply chains and ensure that developers are using only approved application components from trusted sources.

SBOMs In The Event Of A Security Breach

Ideally, an organization will be able to use its SBOMs to detect and remediate vulnerabilities before they trigger a breach. But in the event of an active breach, SBOMs become even more important by helping teams identify which vulnerability opened the door to attack. With that information, they can determine how best to close the vulnerability and end the security incident.

For example, imagine a business that has detected malicious accounts on a server. That’s an indication that the server has been breached, but simply knowing that malicious accounts are present provides little actionable information about how attackers breached the server. By referring to SBOMs for apps hosted on the server, the incident response team could quickly determine whether any apps or their supply chains are subject to vulnerabilities that attackers could exploit to create accounts. Without SBOMs available, the process of determining how attackers breached the machine would likely take much longer and center on guesses and trial-and-error.

Executive Order 14028 And The Importance Of SBOMs

SBOM generation grew even more important following the U.S. government’s release of Executive Order 14028 in 2021. This mandate requires vendors who provide software to the federal government to generate SBOMs for their software so that government agencies can determine quickly whether their supply chains are vulnerable.

Although the SBOM requirements in Executive Order 14028 don’t apply outside the context of U.S. government procurement, they underscore the importance of SBOM generation as a basic best practice that all developers should follow, not just those seeking to do business with federal agencies.

SBOM: Much More Than A Technical Requirement

An SBOM is a strategic asset for supply chain security management, application security and compliance. With SBOMs, businesses can operate quickly and proactively in response to security risks that exist within their software supply chains, rather than waiting to be attacked. They can also establish a culture of transparency and responsibility and embrace a core application security best practice that will only become more important as software supply chains continue to grow in complexity.

With Checkmarx supply chain security solutions like Checkmarx SCA, developers and security teams can easily generate SBOMs for all applications and gain immediate insight into security risks. Checkmarx SBOM generation empowers organizations not just to know what’s at risk in their supply chains, but also to keep SBOMs up to date within constantly changing CI/CD workflows.

Learn more about the role of SBOMs in supply chain security by reading the whitepaper “An Introduction to Open Source Supply Chain Attacks” or the Checkmarx supply chain threat intelligence solution brief.