Modern Authentication with Azure Active Directory for Web Applications

Build advanced authentication solutions for any cloud or web environment

Active Directory has been transformed to reflect the cloud revolution, modern protocols, and today’s newest SaaS paradigms. This is an authoritative, deep-dive guide to building Active Directory authentication solutions for these new environments. Author Vittorio Bertocci drove these technologies from initial concept to general availability, playing key roles in everything from technical design to documentation. In this book, he delivers comprehensive guidance for building complete solutions. For each app type, Bertocci presents high-level scenarios and quick implementation steps, illuminates key concepts in greater depth, and helps you refine your solution to improve performance and reliability. He helps you make sense of highly abstract architectural diagrams and nitty-gritty protocol and implementation details. This is the book for people motivated to become experts.

Active Directory Program Manager Vittorio Bertocci shows you how to:

• Address authentication challenges in the cloud or on-premises
• Systematically protect apps with Azure AD and AD Federation Services
• Power sign-in flows with OpenID Connect, Azure AD, and AD libraries
• Make the most of OpenID Connect’s middleware and supporting classes
• Work with the Azure AD representation of apps and their relationships
• Provide fine-grained app access control via roles, groups, and permissions
• Consume and expose Web APIs protected by Azure AD
• Understand new authentication protocols without reading complex spec documents

Table of Contents

Foreword     xi
Introduction     xiii
Chapter 1: Your first Active Directory app     1
The sample application     1
Prerequisites     1
Microsoft Azure subscription     2
Visual Studio 2015     2
Creating the application     3
Running the application.     4
ClaimsPrincipal: How .NET represents the caller     7
Summary     10
Chapter 2: Identity protocols and application types     11
Pre-claims authentication techniques     12
Passwords, profile stores, and individual applications     12
Domains, integrated authentication, and applications on an   intranet     14
Claims-based identity     17
Identity providers: DCs for the Internet     17
Tokens     18
Trust and claims     20
Claims-oriented protocols     20
Round-trip web apps, first-generation protocols     23
The problem of cross-domain single sign-on     23
SAML     25
WS-Federation     27
Modern apps, modern protocols     31
The rise of the programmable web and the problem of access delegation     32
OAuth2 and web applications     33
Layering web sign-in on OAuth     37
OpenID Connect     39
More API consumption scenarios     44
Single-page applications     45
Leveraging web investments in native clients     47
Summary     49
Chapter 3: Introducing Azure Active Directory and Active Directory Federation Services     51
Active Directory Federation Services     52
ADFS and development     53
Getting ADFS     54
Protocols support     55
Azure Active Directory: Identity as a service     56
Azure AD and development     60
Getting Azure Active Directory     61
Azure AD for developers: Components     63
Notable nondeveloper features     65
Summary     67
Chapter 4: Introducing the identity developer libraries     69
Token requestors and resource protectors     69
Token requestors     70
Resource protectors     73
Hybrids     74
The Azure AD libraries landscape     75
Token requestors     76
Resource protectors     81
Hybrids     85
Visual Studio integration     85
AD integration features in Visual Studio 2013     86
AD integration features in Visual Studio 2015     86
Summary     87
Chapter 5: Getting started with web sign-on and Active Directory     89
The web app you build in this chapter     89
Prerequisites     90
Steps     90
The starting project     90
NuGet packages references     92
Registering the app in Azure AD     93
OpenID Connect initialization code     95
Host the OWIN pipeline     95
Initialize the cookie and OpenID Connect middlewares     96
[Authorize], claims, and first run     97
Adding a trigger for authentication     97
Showing some claims     98
Running the app     99
Quick recap     99
Sign-in and sign-out     99
Sign-in logic     100
Sign-out logic     101
The sign-in and sign-out UI     102
Running the app     103
Using ADFS as an identity provider     103
Summary     105
Chapter 6: OpenID Connect and Azure AD web sign-on     107
The protocol and its specifications     107
OpenID Connect Core 1.0     108
OpenID Connect Discovery     108
OAuth 2.0 Multiple Response Type, OAuth2 Form Post Response Mode     109
OpenID Connection Session Management     109
Other OpenID Connect specifications     109
Supporting specifications     109
OpenID Connect exchanges signing in with Azure AD     110
Capturing a trace     110
Authentication request     113
Discovery     119
Authentication     122
Response     123
Sign-in sequence diagram     126
The ID token and the JWT format     127
OpenID Connect exchanges for signing out from the app and Azure AD     134
Summary     136
Chapter 7: The OWIN OpenID Connect middleware     137
OWIN and Katana     137
What is OWIN?     137
Katana     139
OpenID Connect middleware     155
OpenIdConnectAuthenticationOptions     155
Notifications     159
TokenValidationParameters     167
Valid values     168
Validation flags     169
Validators     169
Miscellany     170
More on sessions     171
Summary     172
Chapter 8: Azure Active Directory application model     173
The building blocks: Application and ServicePrincipal     174
The Application     177
The ServicePrincipal object     187
Consent and delegated permissions     189
Application created by a nonadmin user     189
Interlude: Delegated permissions to access the directory     192
Application requesting admin-level permissions     197
Admin consent     200
Application created by an admin user     204
Multitenancy     205
App user assignment, app permissions, and app roles     211
App user assignment     211
App roles     213
Application permissions     216
Groups     219
Summary     221
Chapter 9: Consuming and exposing a web API protected by Azure Active Directory     223
Consuming a web API from a web application     223
Redeeming an authorization code in the OpenID Connect hybrid flow     224
Using the access token for invoking a web API     232
Other ways of getting access tokens     251
Exposing a protected web API     253
Setting up a web API project     253
Handling web API calls     258
Exposing both a web UX and a web API from the same Visual Studio project     265
A web API calling another API: Flowing the identity of the caller and using “on behalf of”     266
Protecting a web API with ADFS “3”     271
Summary     272
Chapter 10: Active Directory Federation Services in Windows Server 2016 Technical Preview 3     273
Setup (for developers)     273
The new management UX     274
Web sign-on with OpenID Connect and ADFS     276
OpenID Connect middleware and ADFS     276
Setting up a web app in ADFS     277
Testing the web sign-on feature     280
Protecting a web API with ADFS and invoking it from a web app     281
Setting up a web API in ADFS     281
Code for obtaining an access token from ADFS and invoking a web API     285
Testing the web API invocation feature     288
Additional settings     289
Summary     292
Appendix: Further reading     293
Index     295

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