OAuth 2.0 Security Best Current Practice
draft-ietf-oauth-security-topics-12
Web Authorization Protocol T. Lodderstedt
Internet-Draft yes.com
Intended status: Best Current Practice J. Bradley
Expires: September 9, 2019 Yubico
A. Labunets
Facebook
D. Fett
yes.com
March 8, 2019
OAuth 2.0 Security Best Current Practice
draft-ietf-oauth-security-topics-12
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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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 September 9, 2019.
Copyright Notice
Copyright (c) 2019 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
Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
Lodderstedt, et al. Expires September 9, 2019 [Page 1]
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Structure . . . . . . . . . . . . . . . . . . . . . . . . 4
1.2. Conventions and Terminology . . . . . . . . . . . . . . . 4
2. The Updated OAuth 2.0 Attacker Model . . . . . . . . . . . . 4
3. Recommendations . . . . . . . . . . . . . . . . . . . . . . . 6
3.1. Protecting Redirect-Based Flows . . . . . . . . . . . . . 6
3.1.1. Authorization Code Grant . . . . . . . . . . . . . . 7
3.1.2. Implicit Grant . . . . . . . . . . . . . . . . . . . 7
3.2. Token Replay Prevention . . . . . . . . . . . . . . . . . 8
3.3. Access Token Privilege Restriction . . . . . . . . . . . 8
4. Attacks and Mitigations . . . . . . . . . . . . . . . . . . . 9
4.1. Insufficient Redirect URI Validation . . . . . . . . . . 9
4.1.1. Redirect URI Validation Attacks on Authorization Code
Grant . . . . . . . . . . . . . . . . . . . . . . . . 9
4.1.2. Redirect URI Validation Attacks on Implicit Grant . . 10
4.1.3. Proposed Countermeasures . . . . . . . . . . . . . . 12
4.2. Credential Leakage via Referrer Headers . . . . . . . . . 12
4.2.1. Leakage from the OAuth Client . . . . . . . . . . . . 13
4.2.2. Leakage from the Authorization Server . . . . . . . . 13
4.2.3. Consequences . . . . . . . . . . . . . . . . . . . . 13
4.2.4. Proposed Countermeasures . . . . . . . . . . . . . . 13
4.3. Attacks through the Browser History . . . . . . . . . . . 14
4.3.1. Code in Browser History . . . . . . . . . . . . . . . 14
4.3.2. Access Token in Browser History . . . . . . . . . . . 15
4.4. Mix-Up . . . . . . . . . . . . . . . . . . . . . . . . . 15
4.4.1. Attack Description . . . . . . . . . . . . . . . . . 15
4.4.2. Countermeasures . . . . . . . . . . . . . . . . . . . 17
4.5. Authorization Code Injection . . . . . . . . . . . . . . 18
4.5.1. Attack Description . . . . . . . . . . . . . . . . . 18
4.5.2. Discussion . . . . . . . . . . . . . . . . . . . . . 19
4.5.3. Proposed Countermeasures . . . . . . . . . . . . . . 20
4.6. Access Token Injection . . . . . . . . . . . . . . . . . 21
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