Changes between Initial Version and Version 1 of Potential risks and mitigations

Timestamp:

04/30/25 10:48:43 (3 weeks ago)

Author:

enno

Comment:

--

Potential risks and mitigations

@@ +1 @@
+= Potential risks
+
+== Mitigation strategies
+
+Recommendations specific to Guix in air-gapped, classified use
+
+=== Security Risks in an Air-Gapped Guix Workflow
+
+==== Supply Chain Attacks via Source Code
+
+Even though you're building from source, the upstream source code (tarballs, Git repos) may be maliciously modified.
+Guix uses cryptographic hash verification, but only against what is declared in the Guix package definition — not against independent trust anchors.
+
+'''Mitigations:'''
+
+* Use guix build --source with hash-locked package definitions (content-addressed derivations).
+
+* Use reproducible builds and determinism checks (e.g., compare build outputs across trusted builders).
+
+* Consider maintaining a private mirror of trusted source code, and pin hash checks yourself.
+
+* Use content scanning tools (e.g., static analyzers) on all .tar.gz and Git checkouts.
+
+==== Compromise via Channel Updates
+
+Your Guix package definitions come from Git channels (e.g., guix.git, or your own).
+
+If your channel is compromised, malicious package definitions could be delivered.
+
+'''Mitigations:'''
+
+* Use a pinned commit hash in your channels.scm.
+
+* Verify the channel commit with signed Git commits or tags (Guix supports this).
+
+* Host your own internal Guix channel for critical environments — control what definitions are trusted.
+
+* Use guix time-machine to avoid rolling updates.
+
+==== Media Transfer Risks (USB, SD cards)
+
+USB drives used for transferring .nar files or source archives can be a vector for malware, even in an air-gapped setup.
+
+'''Mitigations:'''
+
+* Always format and scan USB media on a controlled, known-clean staging machine before inserting into classified systems.
+
+* Use write-once optical media (DVD-R) where appropriate for immutable transfer.
+
+* Prefer hash verification of transferred files (sha256sum sources.nar) using offline-known-good hashes.
+
+==== Build Environment Leakage
+
+If the build process writes temporary files or outputs data to places outside the Guix store, secrets or traces of sensitive data could leak or persist.
+
+'''Mitigations:'''
+
+* Use guix build inside a dedicated, minimal, reproducible system (e.g., a guix system vm).
+
+* Enable build sandboxing (enabled by default in Guix).
+
+* Disable networking in builders if not already (Guix does this by default, but confirm your configuration).
+
+* Consider full-disk encryption for the build system.
+
+==== Tampered Nar Archives
+
+.nar archives imported into your air-gapped server could be tampered with in transit.
+
+'''Mitigations:'''
+
+* Sign the archive on the export side and verify the signature on the import side.
+
+* Use GPG or minisign for signing hashes.
+
+* Maintain a hash whitelist of approved .nar files on the classified system.
+
+* Store all .nar imports in a sealed append-only log for auditing.
+
+== High-Security Recommendations for Guix in Classified Environments
+
+|| '''Concern''' || '''Recommendation''' ||
+|| Source authenticity  || Use fixed-output derivations with pinned hashes ||
+|| Package definition trust || Host internal Guix channel; pin commit hashes ||
+|| Archive integrity || Sign .nar files and verify signatures ||
+|| Reproducibility || Use multiple offline builders to cross-check outputs ||
+|| Logging || Keep an audit trail of all imports and builds ||
+|| Isolation || Build in virtual machines or system containers with no network ||
+|| Transfer media || Sanitize USBs or use write-once optical media ||
+|| User separation || Separate users for import, build, audit, and deployment tasks ||
+
+== Final Thoughts
+
+Guix offers an excellent foundation for secure, reproducible software environments.
+
+But air-gapped security is about the whole process, not just the tooling.
+
+You should treat the Guix channel, source transport, build environment, and auditability as a single trusted pipeline.