Why SBOM is Critical for Compliance Under the EU Cyber Resilience Act (CRA)

Key Takeaways 

• SBOM enhances transparency by providing a structured inventory of software components, supporting security by design principles. 
• The EU Cyber Resilience Act (CRA) mandates SBOM as part of security and compliance obligations for products with digital elements. 
• TR-03183 requires SBOMs to be machine-readable (JSON/XML) and conform to SPDX or CycloneDX 1.5+, facilitating automated vulnerability handling. 
• SBOMs do not contain vulnerability information but facilitate external vulnerability assessments (e.g., VEX, CSAF) as part of risk assessment processes. 
• CLOUDYRION helps organizations implement SBOMs, cryptographic signing, and compliance measures to meet EU CRA EU requirements. 

The EU CRA addresses these risks by enforcing transparent software security documentation, which includes mandatory SBOMs as a cornerstone of supply chain security. 

One of the biggest challenges in software security is lack of visibility into third-party dependencies. Many organizations rely on third-party software components, yet they lack full visibility into what’s inside their applications. This makes it difficult to detect and respond to vulnerabilities, leading to increased risks of cyberattacks. Without a structured SBOM, organizations struggle to: 

• Detect and respond to vulnerabilities effectively, including actively exploited vulnerabilities. 
• Maintain compliance with regulatory requirements, such as those outlined in the NIS2 Directive. 
• Ensure software integrity and security, which are key aspects of secure by default principles. 

To tackle these issues, BSI’s TR-03183 mandates a machine-processable SBOM format that includes cryptographic integrity, metadata tracking, and structured dependencies. This approach aligns with the European cybersecurity certification scheme and supports the conformity assessment process required by the CRA. 

By implementing SBOM practices, organizations can achieve greater security, regulatory compliance, and risk mitigation in line with the CRA and other horizontal cybersecurity requirements. 

Understanding SBOM and Its Role in Compliance 

A Software Bill of Materials is essentially a detailed inventory of software components, similar to an ingredient list for software. TR-03183 defines SBOM as a machine-readable document that supports automated security processing, which is crucial for managing the attack surface of products with digital elements. 

Mandatory SBOM Elements (TR-03183-2) 

A compliant SBOM MUST include: 

• Component Name & Version – Ensuring traceability of dependencies. 
• Component Creator (Vendor/Supplier URL or Email) – Identification of software sources. 
• Licensing Information – Both declared and concluded licenses. 
• Cryptographic Hash (SHA-512) – Ensuring deployable component integrity. 
• File Properties – Whether the component is executable, an archive, or structured. 
• Timestamp – Date and time of SBOM creation. 
• Dependency Tracking – At least to the first external component. 

Without these mandatory fields, an SBOM does not meet compliance with TR-03183 and, by extension, the CRA requirements. 

Common SBOM Formats 

To ensure compatibility, SBOMs MUST be formatted in JSON or XML and follow one of these standards: 

1. CycloneDX (Version 1.5 or higher)
   Focused on security applications (preferred for CRA compliance). 
2. SPDX (Version 2.2.1 or higher)
   Widely used for software package descriptions and licensing. 
3. SWID Tags 
   Less common, but used in enterprise settings. 

SBOM and VEX (TR-03183 Compliance) 

One common misconception is that SBOMs include vulnerability data. This is incorrect. 

BSI TR-03183 explicitly states that SBOMs MUST NOT contain vulnerability information. This separation supports more effective vulnerability handling processes. 

Instead, organizations should combine SBOMs with separate vulnerability reports using: 

• VEX (Vulnerability Exploitability eXchange) – Provides context on whether a vulnerability is exploitable. 
• CSAF (Common Security Advisory Framework) – A standardized format for security advisories. 

Best Practice: Use SBOM for component transparency and VEX for vulnerability impact analysis. 

Integrating SBOMs into CI/CD Pipelines 

SBOMs should be integrated into the software lifecycle, ensuring they are generated and updated automatically at each build stage. By continuously monitoring dependencies and validating SBOMs with tools like Syft and Trivy, organizations can prevent security risks before deployment. Secure build pipelines play a critical role in mitigating software supply chain threats and supporting the product lifecycle

01 Plan Define SBOM requirements (depth, format, compliance). Establish policies for dependency tracking and supply chain security. Select tools for automated SBOM generation (e.g., Suft, Trivy).	02 Code Document third-party components and licensing information. Ensure code annotations support future SBOM generation. Identify and track open-source dependencies.	03 Build Generate Build SBOM using CI/CD pipelines. Validate SBOM data for missing metadata or outdated dependencies. Use automated tools (Svft, Anchore, SPDX, CvcloneDX).	04 Test Validate SBOM against BSI TR-03183 requirements. Ensure cryptographic hashes (SHA-512) for component integrity. Check for dependency resolution issues.
05 Release Sign SBOMs using cryptographic signatures (Sigstore, Cosign). Store SBOMs securely for auditability. Ensure SBOMs are attached to software artifacts.	06 Deploy Include SBOMs in deployment pipelines. Verify SBOM authenticity before production rollout. Ensure compliance with EU CRA & TR-03183. compliance	07 Operate Maintain an updated SBOM repository. Support runtime SBOM monitoring. Enable automated compliance auditing.	08 Monitor Use VEX & CSAF reports to track vulnerabilities in SBOM components. Perform continuous security scanning. Automate threat intelligence integration.

BSI TR-03183 guideline requires that SBOMs be integrated into secure software development pipelines to ensure end-to-end traceability. 

Best Practices: 

• Generate SBOMs automatically at each build stage. 
• Use dependency tracking tools (Syft, Grype, OWASP Dependency-Check) to detect vulnerabilities before deployment. 
• Ensure secure software builds using SLSA (Supply Chain Levels for Software Artifacts). 
• Sign SBOMs cryptographically using Sigstore’s Cosign. 

Example Workflow: 

1. Developers commit code → Triggers SBOM generation. 
2. Build process integrates SBOM → Ensures transparency. 
3. Security tools analyze SBOM → Identify potential risks. 
4. Final build artifacts & SBOM are cryptographically signed. 
5. Deployment includes signed SBOM → Enables regulatory audits. 

This approach ensures compliance while minimizing security risks and supporting software resilience. 

Cryptographic Hashing and Signing for SBOM Integrity 

Ensuring the integrity of an SBOM is as important as having one. Techniques such as code signing, checksum validation, and digital signatures help prevent tampering and unauthorized modifications, aligning with the secure by default principles of the CRA. 

• Code Signing: Developers use cryptographic signatures to verify software authenticity. 
• Checksum Validation: Ensures files remain unchanged using hash functions like SHA-256. 
• SBOM Signing: Tools like Sigstore’s Cosign allow organizations to sign SBOMs for added security. 

Secure Software Build Pipelines and SBOM Integration 

For an SBOM to be truly effective, it must be embedded in secure development pipelines. Best practices include: 

• Reproducible Builds: Ensuring the same code always produces the same output. 
• Build Provenance Tracking: Using Supply Chain Levels for Software Artifacts (SLSA) to verify where and how software is built. 
• Ephemeral Build Environments: Using temporary, clean build environments to prevent persistent threats. 

With the CRA, SBOMs are no longer optional – sectors like energy, healthcare, finance, and transportation rely on digitial products that must meet strict regulatory standards. Without SBOM compliance, organizations risk non-compliance penalties. SBOM enhances resilience by: 

• Providing visibility into third-party components to reduce supply chain risks. 
• Supporting proactive vulnerability management through automated security scans. 
• Facilitating incident response by quickly identifying affected components. 
• Ensuring software provenance and authenticity with cryptographic signing. 

These practices are particularly crucial for all companies offering products with digital elements in the EU market, regardless of their location.  

At CLOUDYRION, we specialize in helping businesses navigate the complexities of cybersecurity compliance. Our expertise in SBOM implementation, cryptographic signing, and secure development pipelines ensures your organization stays ahead of evolving regulations. Contact us today to learn how we can help fortify your software supply chain and ensure compliance with the EU CRA, including assistance with conformity assessment processes and meeting the support period requirements for critical products.