OAuth 1.0, 2.0 & Beyond: A Complete Technical Research on History, Architecture, CVEs, Lab Deployment & Security Hardening

<p>This paper delivers a comprehensive technical analysis of OAuth 1.0, OAuth 2.0, OpenID Connect, and the emerging OAuth 2.1 framework. It traces the evolution from the pre-OAuth password anti-pattern through OAuth 1.0’s cryptographic signatures to OAuth 2.0’s bearer-token model and OAuth 2.1’s mandatory security enhancements (PKCE everywhere, removal of Implicit and ROPC grants, exact redirect URI matching, and refresh-token rotation).</p> <p>The research examines core architectural components (Authorization Server, Resource Server, Client), all major grant types (Authorization Code + PKCE, Client Credentials, Device Flow), JWT structure and claims, and the critical distinction between Authentication (AuthN) and Authorization (AuthZ). It catalogs high-impact CVEs and attack vectors, including Session Fixation, Covert Redirect, CSRF on OAuth callbacks, Open Redirect, Consent Phishing (APT29/Midnight Blizzard), token leakage via Referer, and the “alg:none” attack, along with precise mitigations.</p>