OAuth 2.0 Security Best Current Practice
draft-ietf-oauth-security-topics-11
Web Authorization Protocol T. Lodderstedt
Internet-Draft yes.com
Intended status: Best Current Practice J. Bradley
Expires: 1 July 2019 Yubico
A. Labunets
Facebook
D. Fett
yes.com
28 December 2018
OAuth 2.0 Security Best Current Practice
draft-ietf-oauth-security-topics-11
Abstract
This document describes best current security practice for OAuth 2.0.
It updates and extends the OAuth 2.0 Security Threat Model to
incorporate practical experiences gathered since OAuth 2.0 was
published and covers new threats relevant due to the broader
application of OAuth 2.0.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
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Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on 1 July 2019.
Copyright Notice
Copyright (c) 2018 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
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Please review these documents carefully, as they describe your rights
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Table of Contents
1. Introduction
2. Recommendations
2.1. Protecting Redirect-Based Flows
2.1.1. Authorization Code Grant
2.1.2. Implicit Grant
2.2. Token Replay Prevention
2.3. Access Token Privilege Restriction
3. Attacks and Mitigations
3.1. Insufficient Redirect URI Validation
3.1.1. Attacks on Authorization Code Grant
3.1.2. Attacks on Implicit Grant
3.1.3. Proposed Countermeasures
3.2. Credential Leakage via Referrer Headers
3.2.1. Leakage from the OAuth client
3.2.2. Leakage from the Authorization Server
3.2.3. Consequences
3.2.4. Proposed Countermeasures
3.3. Attacks through the Browser History
3.3.1. Code in Browser History
3.3.2. Access Token in Browser History
3.4. Mix-Up
3.4.1. Attack Description
3.4.2. Countermeasures
3.5. Authorization Code Injection
3.5.1. Proposed Countermeasures
3.6. Access Token Injection
3.6.1. Proposed Countermeasures
3.7. Cross Site Request Forgery
3.7.1. Proposed Countermeasures
3.8. Access Token Leakage at the Resource Server
3.8.1. Access Token Phishing by Counterfeit
Resource Server
3.8.2. Compromised Resource Server
3.9. Open Redirection
3.9.1. Authorization Server as Open Redirector
3.9.2. Clients as Open Redirector
3.10. 307 Redirect
3.11. TLS Terminating Reverse Proxies
3.12. Refresh Token Protection
4. Acknowledgements
5. IANA Considerations
6. Security Considerations
7. Normative References
Appendix A. Document History
Authors' Addresses
1. Introduction
It's been a while since OAuth has been published in [RFC6749] and
[RFC6750]. Since publication, OAuth 2.0 has gotten massive traction
in the market and became the standard for API protection and, as
foundation of OpenID Connect [OpenID], identity providing. While
OAuth was used in a variety of scenarios and different kinds of
deployments, the following challenges could be observed:
* OAuth implementations are being attacked through known
implementation weaknesses and anti-patterns (CSRF, referrer
header). Although most of these threats are discussed in the
OAuth 2.0 Threat Model and Security Considerations [RFC6819],
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