OAuth 2.0 Threat Model and Security Considerations
draft-ietf-oauth-v2-threatmodel-04

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Last updated 2012-05-25
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Web Authorization Protocol (oauth)                   T. Lodderstedt, Ed.
Internet-Draft                                       Deutsche Telekom AG
Intended status: Informational                                M. McGloin
Expires: November 26, 2012                                           IBM
                                                                 P. Hunt
                                                      Oracle Corporation
                                                            May 25, 2012

           OAuth 2.0 Threat Model and Security Considerations
                   draft-ietf-oauth-v2-threatmodel-04

Abstract

   This document gives additional security considerations for OAuth,
   beyond those in the OAuth specification, based on a comprehensive
   threat model for the OAuth 2.0 Protocol.

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 November 26, 2012.

Copyright Notice

   Copyright (c) 2012 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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   publication of this document.  Please review these documents
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   the Trust Legal Provisions and are provided without warranty as

Lodderstedt, et al.     Expires November 26, 2012               [Page 1]
Internet-Draft             OAuth 2.0 Security                   May 2012

   described in the Simplified BSD License.

Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  6
   2.  Overview . . . . . . . . . . . . . . . . . . . . . . . . . . .  6
     2.1.  Scope  . . . . . . . . . . . . . . . . . . . . . . . . . .  6
     2.2.  Attack Assumptions . . . . . . . . . . . . . . . . . . . .  7
     2.3.  Architectural assumptions  . . . . . . . . . . . . . . . .  7
       2.3.1.  Authorization Servers  . . . . . . . . . . . . . . . .  8
       2.3.2.  Resource Server  . . . . . . . . . . . . . . . . . . .  8
       2.3.3.  Client . . . . . . . . . . . . . . . . . . . . . . . .  8
   3.  Security Features  . . . . . . . . . . . . . . . . . . . . . .  9
     3.1.  Tokens . . . . . . . . . . . . . . . . . . . . . . . . . .  9
       3.1.1.  Scope  . . . . . . . . . . . . . . . . . . . . . . . . 10
       3.1.2.  Expires_In . . . . . . . . . . . . . . . . . . . . . . 10
     3.2.  Access Token . . . . . . . . . . . . . . . . . . . . . . . 11
     3.3.  Refresh Token  . . . . . . . . . . . . . . . . . . . . . . 11
     3.4.  Authorization Code . . . . . . . . . . . . . . . . . . . . 12
     3.5.  Redirection URI  . . . . . . . . . . . . . . . . . . . . . 12
     3.6.  State parameter  . . . . . . . . . . . . . . . . . . . . . 12
     3.7.  Client Identity  . . . . . . . . . . . . . . . . . . . . . 12
   4.  Security Threat Model  . . . . . . . . . . . . . . . . . . . . 14
     4.1.  Clients  . . . . . . . . . . . . . . . . . . . . . . . . . 15
       4.1.1.  Threat: Obtain Client Secrets  . . . . . . . . . . . . 15
       4.1.2.  Threat: Obtain Refresh Tokens  . . . . . . . . . . . . 16
       4.1.3.  Threat: Obtain Access Tokens . . . . . . . . . . . . . 18
       4.1.4.  Threat: End-user credentials phished using
               compromised or embedded browser  . . . . . . . . . . . 18
       4.1.5.  Threat: Open Redirectors on client . . . . . . . . . . 19
     4.2.  Authorization Endpoint . . . . . . . . . . . . . . . . . . 19
       4.2.1.  Threat: Password phishing by counterfeit
               authorization server . . . . . . . . . . . . . . . . . 20
       4.2.2.  Threat: User unintentionally grants too much
               access scope . . . . . . . . . . . . . . . . . . . . . 20
       4.2.3.  Threat: Malicious client obtains existing
               authorization by fraud . . . . . . . . . . . . . . . . 21
       4.2.4.  Threat: Open redirector  . . . . . . . . . . . . . . . 21
     4.3.  Token endpoint . . . . . . . . . . . . . . . . . . . . . . 21
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