What Is a Software Bill of Materials (SBOM)?

Around this time last year, in 2023, the Security and Exchange Commission issued a press release about a lawsuit against an Austin, Texas-based software company. The lawsuit echoed a concern that’s been baffling software companies across the globe—software supply chain security. Cyber threat actors have been targeting software supply chains for some time now, exploiting vulnerabilities like the one in the Log4j framework for installing malware. This rising concern for supply chain security is a major reason why the Software Bill Of Materials (SBOM) is finding its place in official administrative regulations for cybersecurity. Software supply chains are often complicated with multiple processes involved. SBOM helps with visibility into the supply chains by listing the different components and dependencies that these processes directly engage with. Therefore, to efficiently strategize software supply chain risk management, we must understand SBOM and its scope.

Introduction to SBOM (Software Bill of Materials)

A Software Bill Of Materials (SBOM) is a detailed list of the various parts of software, including its open-source components, libraries, and their relationships. The idea is to empower stakeholders with a thorough understanding of everything the software brings, thereby ensuring transparency in the cybersecurity context. With transformations in the ways software is developed and delivered, complexities have emerged that allow cyber attackers to invent creative ways to act. SBOM, therefore, is an essential safety net that allows a sense of visibility into our applications.

Why Is SBOM Essential for Cybersecurity?

When President Biden emphasized SBOM in his executive order regarding cybersecurity improvement, it was in cognizance of the vulnerabilities in the supply chain that malicious campaigns target. A nested list like SBOM essentially breaks the software into its ingredients and helps identify these vulnerabilities. Here are three ways that make SBOM essential for cybersecurity:

• Transparency in software: SBOM helps the stakeholders identify if there are any outdated or risk-prone components in the software. If there is, for instance, an outdated encryption library, or a logging framework like Log4j, the security experts can easily identify the associated risk.
• Tracking open-source components: A lot of modern software solutions encourage the integration of open-source components and libraries. These might not always be checked for their security aspect and SBOM, therefore, helps track them for their potential risks.
• Dependency assessment: While some components may not visibly pose any cybersecurity threat, their dependency on other components or libraries might. Therefore, SBOM also helps security experts look into these dependencies and identify any security gaps.
• Supply chain security: Transparency within the supply chain regarding the security posture of various software components helps ensure proactive security strategies against potential exploitation. SBOM offers the buyers all the necessary information that can enable these strategies for supply chain security.
• Compliance management: SBOM also helps the stakeholders assess the software solutions and their components for regulatory compliance. With strict regulations across industries including healthcare, fintech, defense, and more, compliance failure by any software component can be easily detected.

Key Components of an SBOM (Software Bill of Materials)

NTIA’s report, in accordance with the President’s executive order, suggested three inter-related constituents in an SBOM that are deemed to offer the required transparency into the software. These “minimum elements” can provide a detailed view of the technology and functional blueprint of the software, making it visible for a thorough security assessment.

• Data fields: This element ascertains the details about the software components in a formal SBOM structure. Data fields include supplier name, component version, and dependency relationship among others to help track potential security vulnerabilities.

• Automation support: Automation supports offer the required data formats that can enable easy navigation of SBOM data and machine-readability of software components. This is an essential element to ensure faster and autonomous auditing of the software. CycloneDX,  SPDX, and SWID tags are the three acceptable formats as per the report.

• Processes: These are the necessary practices that would help incorporate SBOM generation and management into the secure development lifecycle of the software. These practices dictate various aspects of SBOM including its generation frequency, the depth components and dependencies included, and known/unknown dependencies, among others.

Benefits of Implementing SBOM (Software Bill of Materials)

A survey in 2022 suggests that 53% of businesses across industries report SBOMs to be an affirmative tool for reporting and compliance. Such a positive embrace of SBOM can only be attributed to the inherent attention to detail that these bills offer. It is this attention to detail that, in turn, leads to a lot of benefits by SBOM:

• Transparency across the supply chain: The data fields and relationships noted by SBOMs help with a detailed overview of the entire software supply chain. The different versions of software components, their dependencies and compatibilities across the software, and their security risks can all be easily identified and analyzed.
• Consistent security posture: Even for the software that are procured despite potential risks suggested by their SBOM, the security admins can be better prepared for any vulnerabilities. Proactive measures can be taken based on the SBOM to mitigate any security risks.
• Compliance management: While SBOM itself is a regulatory mandate, it also helps stakeholders adhere to strict compliance with regulations meant for certain components of the software. Moreover, with regular audits, SBOM can also help identify any deviations in compliance.
• Third-party threats: Any security risks posed by open-source third-party components in the software can be easily tracked with the help of SBOM. Even if the vendor knowingly or unknowingly overlooks a security vulnerability, SBOM can help trace it back to the culprit third-party component.

How to Create and Manage an SBOM?

There are tools available to create an SBOM with all its necessary elements. Such tools serve the essential function of translating their analysis of the software components into any of the desired SBOM standards like SPDX, CycloneDX, and more. These SBOM-generating tools can also help the stakeholders track any obsolete dependencies, licenses, and other such aspects that can lead to security vulnerabilities. Here’s how these tools work:

• Step 1 – Integrating the SBOM tool into the CI/CD pipeline: In order to record the various components of the software code the SBOM tools needs to be integrated with the CI/CD pipeline. These tools can be installed on-premise or on cloud-environment as per convenience.
• Step 2 – Scanning the code repository: Next, the tool scans the code to identify the different components, libraries, open-source frameworks, and more in the software.
• Step 3 – Translating the code analysis: Once the codebase is scanned for all components and dependencies, the data is then translated into one of the standard SBOM formats as desired.
• Step 4 – Generation of SBOM: The translated SBOM data can finally be exported in XML or JSON format for further review. The NTIA reports mandating the generation of new SBOM each time there is an update in the software component.

SBOM Standards and Guidelines

The standards and guidelines for generating SBOM help maintain uniformity in the SBOM structure while covering all the bases in the nested list of software components, libraries, and more. These guidelines are also necessary to encourage the automated generation and processing of SBOM.

• System Package Data Exchange (SPDX): This open standard can help build a readable language that can be translated into file formats like XML, JSON, YAML, and more. The standard can efficiently outline the different software components during development as well as deployment by collecting data in the form of creation information, file information, package information, and more.
• CycloneDX: This format was released with a dedicated focus on security and automated SBOM generation. The lightweight specification can ensure a thorough analysis of software components, their interaction with external services, and the relationships among them. The open-source standard also sits well with the dynamic open-source components that are modified and redistributed on a regular basis.
• Software Identification Tags (SWID Tags): Established by ISO in 2012, SWID tags are meant to track the software component throughout its lifecycle. These tags—namely, primary, patch, corpus, and supplemental—are added once the software is installed to provide details on the installer, installation, patches, and other aspects of a software component.

SBOM (Software Bill of Materials) Challenges

The challenges in SBOM arise mostly regarding the generation part of it, given its deeply structured and formal nature. This is how these challenges manifest:

• Maturity of SBOM tools: While the tools are consistently evolving to abide by standardized SBOM formats and structures, there are still some gaps. Moreover, operating these tools is also a hassle that different stakeholders find hard to navigate given the lack of good interfaces, interfaces, and interoperability, among other factors.
• Slow adoption and integration: There are still third-party vendors who fail to abide by the SBOM mandate due to which there’s a lag in the adoption and integration of SBOM resources especially with open-source software.
• Continuity in SBOM generation: Making SBOM generation a continuous process, so that it occurs at different stages of the SDLC, is still not achieved by businesses. Though it is an aspiration for most of the businesses dealing with SBOMs, a lot of them haven’t achieved it yet.
• Additional security concerns: There are security experts who also claim that blanket vulnerability management cannot protect digital ecosystems from external threats. Organizations need to prioritize what vulnerabilities they want to address and strategize accordingly. This is a difficult feat to achieve while working with SBOMs thanks to the added complexity.

Best Practices for Ensuring Effective SBOM Usage

Generating SBOM is already a good practice. The best practice would be to generate it consistently and throughout the SDLC. Here are some other practices that can make that happen and maximize the utility of SBOM for supply chain security:

• Generate early, and update regularly: It is essential that SBOMs are generated as early in the SDLC as possible so that every added dependency can be recorded from early on. The regular updates in SBOM will make sure that all builds and releases of the various software components are duly noted in the bill.
• Automated SBOM generation: Since automation support is an essential part of SBOM, it would only make sense to have automation resources for generating it. Automation would also ensure the regular generation of bills through the SDLC.
• Standardized formats: Formats like SPDX or CycloneDX have the required depth to truly capture security-sensitive SBOM data. Using such standardized formats would ensure the bill’s interoperability and machine-readability.
• Version control: Version control in SBOMs will ensure that any new changes built or released in the software component can be easily tracked for security assessment. This also makes the SBOM more accountable when managing dependencies.

SBOM Use Cases

While its primary utility is offering critical insights into software vulnerability, SBOM can cater to a lot of use cases, some of which include:

• Software Security: SBOMs can help security teams precisely identify vulnerable parts of the software code. The teams can use it to seek and address any parts of software prone to exploitation by cyber attackers.

• Supply chain security: Many government institutions, including the US and some European governments, have mandated the inclusion of SBOMs in the software supply chains. Experts predict that soon they might be available to the end customers as well.

• Ease of procurement: With businesses across industries anxious about cybersecurity mishaps, SBOMs inspire a sense of confidence in procurement teams looking for a software solution. The offered transparency helped build trust between the two parties.

• Ease of development: Since SBOMs contain a detailed breakdown of the dependencies and relationships between software components, it is easier for developers to work on new components without disrupting any earlier functioning.

Differences Between SBOM vs SCA

Definitely, Software Bill of Materials (SBOM) and Software Composition Analysis (SCA) have overlapping features that can help understand the different constituents of software. Therefore, an informed choice between the two depends on the scope of the software lifecycle for which you want to use them.

Here’s what business leaders need to know to make that choice:

Differences Between BOM vs SBOM

BOM and SBOM sound so similar in their nature that one can be often confused with the other. However, they both belong to very separate domains. While BOM is an inventory more relevant to the manufacturing domain, SBOM has a very specific role within software engineering. Here’s how decision-makers can separate the two:

Conclusion

Being a part of administrative regulations for cybersecurity, SBOM already holds a critical place in the software lifecycle. Security of software supply chains is among the various use cases that it can serve. With distributed architectures, codified infrastructure, and widespread networks, software solutions are now serving more complex business use cases than ever. SBOMs key components and standard formats make it a powerful ally in curbing incidents like Uber and Solarwinds.

Based on our discussion in this blog, business leaders and security experts can follow the best practices to automate SBOM generation and leverage them for supply chain security.

SentinelOne can help you employ features like SBOM to protect your software supply chain. Learn more about our expertise here.

FAQs

1. What is an SBOM, and why is it important?

A software bill of materials, or SBOM, is a detailed breakdown of the various software components, libraries, dependencies, and more in the form of a hierarchical list. It is important to ensure visibility into risk-prone parts of the software code, which can be exploited for cyberattacks.

2. How does an SBOM enhance software supply chain security?

With the deep visibility that SBOM offers, it is easier for security experts to find potential vulnerabilities in the software supply chain and address them effectively.

3. What are the key components of an SBOM?

As per administrative regulations, the key elements of SBOM include data fields, practices and processes, and automation support.

4. How can organizations implement an effective SBOM strategy?

For an effective SBOM strategy, it is essential to follow best practices like early generation, regular updates, automated generation, and integration with CI/CD pipelines.

5. What standards should be followed when creating an SBOM?

Three standards that work best with SBOM are SPDX, CycloneDC, and SWID Tags.

6. How do I get a software bill of materials?

To generate a software bill of materials you can leverage automation tools that can help you with the required formats and outputs. Our experts at SentinelOne can help you with the same.