What Is A Software Bill of Materials (SBOM) & 4 Critical Benefits

What is a software bill of materials (SBOM)?

A Software Bill of Materials (SBOM) is a detailed list of all the ingredients (components, libraries, dependencies, etc.) that make up a piece of software. Similar to a nutritional label on a food product, it provides transparency into what’s inside the software. SBOMs are crucial for identifying and managing potential security vulnerabilities and licensing risks within a software system. 

An SBOM is a comprehensive inventory of all software components, including their versions, licenses, and other relevant information. In addition to open-source components, it also lists all third-party and proprietary components used in the software. SBOMs are typically generated in a machine-readable format, making them easily usable for automated analysis and tracking. 

Here are several reasons why it’s important to have an SBOM:

• Improved transparency: SBOMs provide clear visibility into the components used in a software application, allowing organizations to understand what they are using and potential security risks. 
• Vulnerability management: By knowing the components and their versions, organizations can quickly identify and address vulnerabilities when security flaws are discovered. 
• Supply chain risk management: SBOMs help organizations assess and mitigate risks associated with the software supply chain, including potential disruptions or malicious components. 
• Compliance: SBOMs can be used to demonstrate compliance with various regulations and standards related to software security and licensing. 

Key aspects of an SBOM include:

• Component identification: Clearly identifying each component (name, version, vendor, etc.). 
• Dependency relationships: Showing how components are interconnected and dependent on each other. 
• Licensing information: Providing details about the licenses governing each component. 
• Vulnerability data: Linking components to known vulnerabilities and security advisories. 
• Automated generation and analysis: SBOMs are ideally generated and analyzed using automated tools. 

4 reasons SBOMs are critical to modern software security 

SBOMs play a key role in application security by providing visibility into all components within a software application. Here’s an overview of the crucial advantages of SBOMs.

Improved transparency

SBOMs provide organizations with a clear, structured inventory of all software components, making it easier to understand what’s inside an application. Modern software often integrates dozens or hundreds of third-party libraries and dependencies, many of which are not explicitly documented in source code. Without an SBOM, it’s easy for hidden components to go unnoticed, leaving potential security and licensing issues unaddressed.

By maintaining an up-to-date SBOM, teams can ensure every component—direct and transitive—is accounted for, including their versions and suppliers. This level of transparency allows developers, security teams, and auditors to assess the composition of software quickly and make informed decisions about risk management, updates, and compliance obligations.

Vulnerability management

An SBOM enables faster identification and mitigation of vulnerabilities by mapping each component to known security advisories and CVEs. When a new vulnerability like Heartbleed or Log4Shell is disclosed, organizations with SBOMs can rapidly query their inventory to determine if affected versions are in use and where they reside in their systems. This eliminates guesswork and accelerates response time.

In addition to supporting immediate triage, SBOMs facilitate proactive vulnerability scanning. Security tools can analyze the SBOM data against vulnerability databases on an ongoing basis, ensuring teams are alerted as soon as a relevant issue emerges. This reduces the attack surface and supports a more resilient software lifecycle.

Supply chain risk management

Software supply chains are increasingly targeted by attackers, as seen in incidents like the SolarWinds breach. SBOMs address this risk by making the origins and dependencies of software components explicit. Organizations can evaluate their suppliers, assess the integrity of third-party code, and monitor for untrusted or unexpected additions to their applications.

By analyzing dependency relationships, SBOMs also help uncover “shadow dependencies” that enter through upstream packages. This makes it possible to apply security controls and vet suppliers at every layer of the software stack, reducing exposure to malicious or compromised components in the supply chain.

Compliance

Many industries and governments now require proof of software composition to ensure compliance with security and licensing standards. An SBOM serves as verifiable evidence during audits, helping organizations demonstrate that they’ve identified all components and adhered to relevant obligations, such as those under GDPR, HIPAA, or the U.S. Executive Order on Cybersecurity.

Licensing compliance also benefits from SBOMs by making it easier to track the licenses of open-source and third-party components. Teams can avoid introducing incompatible licenses into their products and ensure that attribution and disclosure requirements are met. This minimizes legal risks and avoids costly delays during product deployment or distribution.

Core components of an SBOM 

Here are the core components typically included in an SBOM:

• Component list: This is the main content of an SBOM, detailing every software package included in a product. Each entry generally includes the component name, version, supplier, and unique identifiers. The list also distinguishes between direct and transitive dependencies, offering a complete inventory.
• Unique identifiers: To ensure clarity and avoid confusion between similarly named packages, SBOMs use identifiers such as package URLs (PURLs), SPDX identifiers, or software identification (SWID) tags. These identifiers help link components to external vulnerability and license databases.
• Metadata: Metadata provides context about the SBOM itself, including the time of creation, tool used, and the authors or maintainers. This helps establish trust in the SBOM’s accuracy and lineage, which is important during audits or incident response.
• Dependency graph: This is an explicit map of how each component depends on others. It’s useful for visualizing component hierarchies and is critical for identifying indirect risks. Some SBOM formats support graph-based structures to make this mapping machine-readable.
• Integrity information: Hash values such as SHA-256 are often included to verify the integrity of each component. These hashes allow consumers to check whether the files match expected values and haven’t been tampered with or altered.

How SBOM tools work 

Here’s an overview of how a Software Bill of Materials operates.

1. Component identification

Component identification is foundational for any SBOM. Each software component—such as a third-party library, plugin, or proprietary module—must be uniquely and consistently described. This includes capturing the component’s name, version, supplier, and, where possible, cryptographic hashes to guarantee integrity. By standardizing how components are identified, SBOMs make it possible to compare software bills of materials from different sources and quickly resolve ambiguities.

Thorough component identification allows teams to correlate vulnerabilities, updates, or licensing changes back to the precise entries in their software. If a critical vulnerability is disclosed in a popular library, organizations can reliably determine whether their applications are affected, which version is present, and where remediation is needed. 

2. Dependency relationships

Dependency relationships specify how different components within a software system are interconnected. SBOMs map both direct and indirect dependencies, clarifying which modules rely on others and exposing transitive inclusion of code. For example, a primary dependency might itself include several sub-dependencies, each carrying their own risks.

Mapping these relationships allows organizations to perform impact assessments when vulnerabilities or license issues are discovered. Rather than just reviewing top-level dependencies, teams can identify the full chain of third-party code included via indirect means. This helps with prioritization, as security and compliance teams can focus their attention where risk converges.

3. Licensing information

Accurate license tracking ensures companies respect intellectual property rights, comply with open source obligations, and avoid legal penalties from inadvertent violations. This information should include the license name, version, and any relevant notices or exceptions for each listed component.

Storing licensing details within an SBOM simplifies compliance checks during procurement, development, and audits. It allows organizations to quickly verify that new dependencies are suitable for their intended use and do not introduce conflicting obligations. Whether responding to a customer’s due diligence request or planning a product launch, complete licensing knowledge reduces the risk of costly delays or legal disputes.

4. Vulnerability data

An effective SBOM will incorporate vulnerability data linked to each component, such as known common vulnerabilities and exposures (CVEs). By correlating components and their associated vulnerabilities, teams can immediately identify and triage risk exposures within applications. Integrating this data helps organizations prioritize patching, remediation, or mitigation activities to reduce the attack surface.

Vulnerability data in SBOMs supports continuous monitoring and proactive defense. As new vulnerabilities are discovered and published, SBOMs can be scanned automatically to check for affected versions in use. This enables a rapid response to evolving threat landscapes and allows teams to address issues before adversaries exploit them. 

5. Automated generation and analysis

Automated SBOM generation is essential for scalability and accuracy, especially in modern CI/CD environments where software changes are frequent. Tools that extract, structure, and update SBOM data with each build eliminate manual errors and keep inventories current. Automation makes it feasible to maintain accurate SBOMs even across large, complex portfolios.

Analysis of SBOMs can also be automated to identify policy violations, outdated packages, or known vulnerabilities. This supports early detection and remediation efforts, triggering alerts or workflow automations as needed. Automated generation and analysis ensure that SBOMs remain a living resource rather than a static, quickly outdated file.

Common SBOM formats and standards 

SPDX

SPDX (software package data exchange) is an open standard maintained by the Linux Foundation. It offers a structured, machine-readable format for documenting components, licenses, and relationships within software. Widely accepted across open source and commercial projects, SPDX files are often formatted in JSON, YAML, RDF, or tag-value formats.

SPDX’s focus on license data and component clarity supports automated compliance checks and detailed risk assessments. Organizations using SPDX can leverage a large ecosystem of compatible tools, improving interoperability. As a transparent, vendor-neutral standard, SPDX enables SBOM sharing between organizations, customers, and regulators with minimal friction.

CycloneDX

CycloneDX is another widely-adopted SBOM specification, created by the OWASP Foundation with an emphasis on security. While it covers the typical SBOM fields—like components and their dependencies—CycloneDX goes further by providing vulnerability mappings, cryptographic hashes, and security-focused metadata. 

CycloneDX supports multiple file formats (including XML, JSON, and Protocol Buffers) and is integrated into numerous build tools and security platforms. Its extensibility allows organizations to capture information relevant to software assurance, such as component provenance and custom fields. 

SWID

Software identification (SWID) tags are an ISO standard (ISO/IEC 19770-2) designed to uniquely identify and catalog software products. SWID tags are typically used for asset management, tracking software installations, and aiding with license compliance. Their XML format includes metadata about a software package, such as its version, creator, and unique identifiers.

While SWID tags are most common in enterprise environments focused on asset discovery and management, they are increasingly incorporated into SBOM workflows for identifying installed components consistently. Using SWID can help organizations extend the value of their SBOMs to IT operations and compliance programs.

Software composition analysis (SCA) vs. SBOM: What is the difference? 

Software composition analysis (SCA) and software bill of materials (SBOM) are closely related but serve different purposes within the software supply chain.

SCA refers to a set of automated tools and processes that analyze software to identify the open source and third-party components it uses. These tools assess the software for known vulnerabilities, license compliance issues, and policy violations. SCA tools are dynamic—they scan source code, binaries, or containers to provide real-time insight into risks and changes as software evolves. They are often integrated into development pipelines to enforce security and compliance policies before release.

SBOMs are static artifacts that list all components within a software product. An SBOM may be generated using SCA tools, but it serves as a formal record that can be shared, audited, and referenced independently. It is primarily a data structure, not an analysis engine. While SBOMs can include vulnerability or license metadata, they do not perform scans themselves—they depend on external sources or integrations for enrichment.

Related content: Read our guide to SBOM audit

Challenges in SBOM implementation

There are several factors that can complicate the maintenance of SBOMs.

Data privacy

One of the key challenges in implementing SBOMs is balancing transparency with data privacy. Organizations may be reluctant to expose details about proprietary software composition or internal dependencies in externally shared SBOMs. This information could give attackers valuable intelligence or reveal competitive secrets.

Maintenance overhead

Keeping SBOMs current is an ongoing effort, especially for complex software projects with rapid release cycles and evolving dependencies. Manual tracking quickly becomes unsustainable, risking outdated or inaccurate records if not actively managed. Changes in underlying libraries, patch releases, or supply chain updates all require SBOM updates.

Tooling limitations

Despite advances in SBOM tooling, limitations persist in terms of support for all programming languages, build environments, and artifact types. Some tools may fail to recognize certain package managers or custom integrations, leading to incomplete or inconsistent SBOMs.  SBOM tool ecosystems are still maturing, and interoperability between formats and vendors can be inconsistent. 

Best practices for implementing SBOMs 

Organizations should consider these practices to improve their SBOM strategy.

1. Define a centralized SBOM policy and governance model

Establishing a centralized policy for SBOM generation and use is essential to ensure consistency across projects and teams. This policy should define what information must be included, how SBOMs are stored and shared, and who is responsible for maintaining them. It should also specify disclosure protocols and retention requirements, especially for externally facing software.

Governance models should include oversight roles that ensure compliance with SBOM standards, internal audits, and periodic reviews. By embedding SBOM practices into organizational policy, companies can scale secure development practices and reduce ad hoc decision-making around software composition transparency.

2. Integrate SBOM creation into DevOps workflows

To ensure SBOMs reflect the actual build state of software, organizations should integrate SBOM generation into their CI/CD pipelines. This means generating SBOMs automatically during builds, releases, or container packaging steps. Embedding this step as part of DevOps ensures that every version of a product has a corresponding SBOM.

This integration allows development teams to catch outdated dependencies, license issues, or policy violations early—before software is deployed. It also standardizes SBOM output formats and content, making downstream consumption by security, legal, and operations teams more reliable.

3. Incorporate AIBOM practices for AI systems

For software that includes machine learning components, organizations should extend SBOM concepts to cover AI artifacts—resulting in an AI bill of materials (AIBOM). This includes listing datasets, model versions, training code, model parameters, and data preprocessing scripts. These elements introduce unique dependencies that must be documented to evaluate trustworthiness, bias, and reproducibility.

AIBOMs help stakeholders understand how AI outputs are produced and what data or tools influenced them. They also support regulatory and ethical requirements for explainability and auditability in AI-enabled systems. 

4. Automate SBOM updates with software changes

SBOMs must evolve as software evolves. Automating SBOM regeneration with every software update ensures that component inventories remain accurate. This involves integrating tooling into source control or deployment workflows to trigger SBOM updates whenever new code, dependencies, or libraries are added.

Automation reduces the risk of outdated SBOMs being used for vulnerability assessments or audits. It also enforces alignment between development and security processes, ensuring changes are evaluated in real time for potential compliance or risk impacts.

5. Validate SBOM completeness and accuracy continuously

SBOMs are only as useful as they are complete and correct. Organizations should regularly audit SBOMs for coverage and precision—checking that all runtime and build-time dependencies are captured and properly described. This includes verifying hash values, dependency relationships, and license entries.

Continuous validation tools can compare SBOM data against actual deployment artifacts or runtime environments to identify discrepancies. This ensures the SBOM reflects what is actually in use, avoiding blind spots in vulnerability and compliance analysis.

Generating and managing SBOMs with Mend.io

Mend.io simplifies and strengthens SBOM management by giving teams the ability to automatically generate, export, and import software bill of materials across SPDX and CycloneDX standards—with support for VEX data. Whether you’re tracking dependencies, auditing for vulnerabilities, or meeting regulatory requirements, Mend.io lets you create SBOMs at the organization, application, or project level. SBOMs can be enriched with additional vulnerability intelligence and seamlessly imported back into Mend.io for continuous governance. The result: always-accurate, security-aware SBOMs that reduce manual effort and improve visibility across your software supply chain