Exposed Secrets in Docker Layers — Securing a Blockchain Infrastructure Pipeline

While building the backend for the Subgraphs product of a leading blockchain infrastructure provider, Falistro conducted a thorough audit of the project’s CI/CD and containerization workflows. Within the first week, the team uncovered a critical security flaw — private library credentials had been inadvertently embedded in a public Docker image layer and pushed to Docker Hub.

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An immediate incident response and remediation plan was put in motion. All compromised keys were rotated, and the Docker build pipeline was refactored to prevent recurrence. The new approach ensured that secrets were mounted dynamically only during the build process, used briefly to fetch private dependencies, and securely discarded before the final image was created — ensuring no trace of sensitive credentials in any Docker layer or build history.

The incident served as a catalyst for a broader DevSecOps enhancement initiative. Falistro implemented multi-stage Docker builds, minimized build contexts, and introduced integrity verification within CI to strengthen the overall supply chain. The resulting system not only eliminated secret leakage risks but also optimized image size, build time, and reproducibility, creating a secure, scalable foundation for subsequent blockchain services.

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This engagement showcased Falistro’s ability to diagnose complex security vulnerabilities in distributed systems and implement resilient, long-term architectural improvements with measurable operational impact.