artifact-provenance-verification

name	artifact-provenance-verification
description	Assess and establish build artifact provenance and integrity — SLSA provenance level, signing/attestation (Sigstore/cosign, in-toto), and verification at deploy/admission. Use when you need to prove an artifact (container image, package, binary) came from the expected source and build, untampered.

Goal

A clear picture of an artifact's provenance maturity and a path to "only verified, attested artifacts are deployed" — so a tampered or unknown-origin artifact can't reach production.

Frame against SLSA

Map the build/artifact flow to a SLSA build level and identify the next gap:

• L1 — provenance exists (build is scripted, provenance generated).
• L2 — provenance is signed and from a hosted build service.
• L3 — build runs on hardened, isolated infrastructure; provenance is non-forgeable. This is the meaningful bar for tamper resistance.

Steps

1. Inventory trust signals — is the artifact signed? By what identity (keyless/OIDC via Sigstore, or a managed key)? Is there a provenance attestation (in-toto / SLSA) linking artifact ↔ source commit ↔ builder?
2. Verify the chain — source → build → artifact → registry → deploy. Confirm the signing identity and provenance are checked, not just present.
3. Find the enforcement gap — is verification required at admission/deploy (e.g., cosign verify in an admission controller / policy gate), or merely available? Unverified-but-signed is theater.
4. Recommend — signing in CI (keyless preferred), provenance generation, verification policy at the gate, and key/identity trust roots + revocation.

Output

A provenance assessment: current SLSA level · signing/attestation state · where verification is (and isn't) enforced · prioritized steps to the next level. Pair with pipeline-integrity-review for the build side and security-diagramming for the chain-of-custody diagram.

Notes

Signing without enforced verification buys nothing — the control is the gate that rejects unverified artifacts. Keyless (OIDC/Fulcio) signing avoids long-lived key management and is the modern default. Provenance must bind artifact → exact source commit → builder, or it can't prove "this came from that build."