OAuth 2.0 Security Best Current Practice
draft-ietf-oauth-security-topics-14

Document Type Active Internet-Draft (oauth WG)
Last updated 2020-02-10
Replaces draft-lodderstedt-oauth-security-topics
Stream IETF
Intended RFC status Best Current Practice
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Document shepherd Hannes Tschofenig
IESG IESG state I-D Exists
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Send notices to Hannes Tschofenig <hannes.tschofenig@arm.com>
Web Authorization Protocol                                T. Lodderstedt
Internet-Draft                                                   yes.com
Intended status: Best Current Practice                        J. Bradley
Expires: August 13, 2020                                          Yubico
                                                             A. Labunets

                                                                 D. Fett
                                                                 yes.com
                                                       February 10, 2020

                OAuth 2.0 Security Best Current Practice
                  draft-ietf-oauth-security-topics-14

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
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   This Internet-Draft will expire on August 13, 2020.

Copyright Notice

   Copyright (c) 2020 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 August 13, 2020                [Page 1]
Internet-Draft            oauth-security-topics            February 2020

   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
     1.1.  Structure . . . . . . . . . . . . . . . . . . . . . . . .   4
     1.2.  Conventions and Terminology . . . . . . . . . . . . . . .   4
   2.  Recommendations . . . . . . . . . . . . . . . . . . . . . . .   5
     2.1.  Protecting Redirect-Based Flows . . . . . . . . . . . . .   5
       2.1.1.  Authorization Code Grant  . . . . . . . . . . . . . .   6
       2.1.2.  Implicit Grant  . . . . . . . . . . . . . . . . . . .   6
     2.2.  Token Replay Prevention . . . . . . . . . . . . . . . . .   7
     2.3.  Access Token Privilege Restriction  . . . . . . . . . . .   7
     2.4.  Resource Owner Password Credentials Grant . . . . . . . .   8
     2.5.  Client Authentication . . . . . . . . . . . . . . . . . .   8
     2.6.  Other Recommendations . . . . . . . . . . . . . . . . . .   8
   3.  The Updated OAuth 2.0 Attacker Model  . . . . . . . . . . . .   8
   4.  Attacks and Mitigations . . . . . . . . . . . . . . . . . . .  10
     4.1.  Insufficient Redirect URI Validation  . . . . . . . . . .  11
       4.1.1.  Redirect URI Validation Attacks on Authorization Code
               Grant . . . . . . . . . . . . . . . . . . . . . . . .  11
       4.1.2.  Redirect URI Validation Attacks on Implicit Grant . .  13
       4.1.3.  Countermeasures . . . . . . . . . . . . . . . . . . .  14
     4.2.  Credential Leakage via Referer Headers  . . . . . . . . .  15
       4.2.1.  Leakage from the OAuth Client . . . . . . . . . . . .  15
       4.2.2.  Leakage from the Authorization Server . . . . . . . .  15
       4.2.3.  Consequences  . . . . . . . . . . . . . . . . . . . .  16
       4.2.4.  Countermeasures . . . . . . . . . . . . . . . . . . .  16
     4.3.  Credential Leakage via Browser History  . . . . . . . . .  17
       4.3.1.  Authorization Code in Browser History . . . . . . . .  17
       4.3.2.  Access Token in Browser History . . . . . . . . . . .  17
     4.4.  Mix-Up Attacks  . . . . . . . . . . . . . . . . . . . . .  18
       4.4.1.  Attack Description  . . . . . . . . . . . . . . . . .  18
       4.4.2.  Countermeasures . . . . . . . . . . . . . . . . . . .  20
     4.5.  Authorization Code Injection  . . . . . . . . . . . . . .  21
       4.5.1.  Attack Description  . . . . . . . . . . . . . . . . .  21
       4.5.2.  Discussion  . . . . . . . . . . . . . . . . . . . . .  22
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