auditing-saml-and-oidc-flowslisted
Install: claude install-skill UnboundCompute/security-agent-skills
# Auditing SAML and OIDC flows: the whole trust rests on one verification
Federated login moves the trust boundary to a signed assertion from an identity
provider, and the entire security rests on the relying party verifying that assertion
exactly. The classic flaws are all failures of that verification: a signature checked
over the wrong element, a token accepted without a signature, an audience or redirect
target not pinned, a flow with no anti-replay value. Each lets an attacker present an
identity that is not theirs.
## When to use
- You are reviewing a SAML or OIDC integration or an identity-provider connection.
- A login trusts an externally-issued, signed assertion or token.
- You are assessing account-linking and how an external identity maps to a local one.
## Scope check
Audit login flows you own or are authorized to test, with test accounts and a test
identity provider. Do not forge assertions against systems you do not control. If you
can't name the authorization, stop.
## The loop
1. **Identify the trusted assertion and where it is verified.** Find the token or
assertion the relying party trusts (a signed SAML assertion, an OIDC id token) and
the exact code that validates it. Everything downstream trusts whatever that check
accepts, so the check is the audit target.
2. **Test signature presence and coverage.** Is every accepted assertion actually
signed, and is the signature verified over the exact element whose contents are
used? Try strip