Skills Development Testing Saml SSO Assertions And Trust Flaws

Testing Saml SSO Assertions And Trust Flaws

v20260506
saml-sso-assertion-attacks
This skill provides a comprehensive playbook for testing the security of SAML-based Single Sign-On (SSO) solutions. It focuses on validating assertion trust by checking signature coverage, audience and recipient restrictions, handling of Assertion Consumer Service (ACS), and identifying potential XML parsing weaknesses or IdP/SP confusion flaws. Use this when evaluating enterprise authentication systems for critical security vulnerabilities.
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Overview

SKILL: SAML SSO and Assertion Attacks — Signature Validation, Binding, and Trust Confusion

AI LOAD INSTRUCTION: Use this skill when the target uses SAML-based SSO and you need to validate assertion trust: signature coverage, audience and recipient checks, ACS handling, XML parsing weaknesses, and IdP/SP confusion.

1. WHEN TO LOAD THIS SKILL

Load when:

  • Enterprise SSO uses SAML requests or responses
  • You see SAMLRequest, SAMLResponse, XML assertions, or ACS endpoints
  • Login flows involve an external IdP and browser POST/redirect binding

2. HIGH-VALUE MISCONFIGURATION CHECKS

Theme What to Check
signature validation unsigned assertion accepted, wrong node signed, signature wrapping
audience and recipient weak Audience, Recipient, Destination, or ACS validation
issuer trust wrong IdP accepted or multi-tenant issuer confusion
replay and freshness missing InResponseTo, weak NotBefore / NotOnOrAfter enforcement
account mapping email-only binding, case folding, unverified attributes
XML parser behavior XXE-like parser issues or unsafe transforms around SAML documents

3. QUICK TRIAGE

  1. Capture one full login round trip.
  2. Inspect which XML nodes are signed and which attributes drive account binding.
  3. Compare SP-initiated and IdP-initiated flows.
  4. Test replay, altered attributes, and assertion placement confusion.

4. RELATED ROUTES

Info
Category Development
Name saml-sso-assertion-attacks
Version v20260506
Size 1.95KB
Updated At 2026-05-08
Language