The question is no longer 'is your code secure?' but 'is your code actually the code you think it is?' Supply chain attacks like SolarWinds proved that compromising the build system is far more effective than attacking the runtime.
What is SLSA (Supply-chain Levels for Software Artifacts)?
Traditional Application Security (AppSec) focuses on finding vulnerabilities in source code (SAST) or running applications (DAST). However, Software Supply Chain Security focuses on the integrity of the process that transforms that source code into a deployable artifact.
For defense contractors and critical infrastructure, this is now a regulatory mandate under Executive Order 14028. The gold standard for meeting these requirements is SLSA.
The SLSA Levels
| Level | Name | Requirements |
|---|---|---|
| L1 | Documentation | Build process is documented. Provenance (metadata about how it was built) exists. |
| L2 | Tamper Resistance | Build service is hosted (not on a dev's laptop). Provenance is authenticated (signed). |
| L3 | Extra Protection | Source and build platforms meet specific hardness criteria. Provenance is non-falsifiable. |
Implementing SBOMs (Software Bill of Materials)
An SBOM is the formal inventory of every component, library, and dependency in your software. It is impossible to manage vulnerability exposure (like Log4j) without a machine-readable SBOM.
CycloneDX vs. SPDX
While both are accepted formats, we recommend CycloneDX for modern cloud-native and microservice architectures due to its lightweight JSON structure and robust support for vulnerability (VEX) flags.
// Example CycloneDX Component Entry
{
"type": "library",
"name": "openssl",
"version": "1.1.1n",
"purl": "pkg:deb/debian/openssl@1.1.1n-0+deb10u3",
"hashes": [
{
"alg": "SHA-256",
"content": "e45a55...7d8e"
}
]
}Wait, Verify, Then Trust: The Sigstore Standard
Generating an SBOM is step one. Verifying it is step two. We utilize Sigstore (Cosign) for keyless signing of container images and artifacts.
This ensures that the artifact deployed in the air-gapped production environment is cryptographically identical to the artifact that passed CI/CD tests.
- Cosign: Signs the container image.
- Rekor: Providing an immutable transparency log of the signing event.
- Policy Controller: A Kubernetes admission controller that rejects any pod without a valid signature.
Conclusion: The Zero Trust Pipeline
In defense environments, "Zero Trust" applies to code just as it applies to networks. By implementing SLSA L3 standards and enforcing rigorous SBOM validation, we ensure that our software supply chain is resilient against even the most sophisticated nation-state threat actors.
Need a stronger answer for release trust?
Our supply chain security service helps teams improve SBOM strategy, signing, provenance, dependency governance, and release integrity where higher-trust buyers are asking harder questions.