The following features are introduced for Kerberos authentication in Windows Server and Windows 8 to enable you to build more robust applications. Extended Protection for Authentication is designed to protect against authentication relay attacks. It uses a combination of channel binding and service binding techniques. Extended Protection was introduced in Windows 7 and made available on a number of previously released operating systems. Extended Protection relies on a collaboration of client-side and server-side technologies and a specific set of rules.
For example, one rule is that the target of authentication, the Service Principal Name SPN , must be intentional—even when a user is lured into authentication. The target SPN must be derived from user intent, and not from an untrusted source.
This allows services that are configured for Extended Protection to handle authentication to an untrusted source securely. Because NTLM and Kerberos clients that are attempting to authenticate using an untrusted SPN state that explicitly in their authentication messages, the services then will allow or fail the authentication request based on its Extended Protection configuration:.
In Windows 7, when the user signed in by using a smart card with a mapped group, the group was lost when the user connected to resources outside the branch office. A device running Windows 8 in a branch office uses a hub domain controller running Windows Server to get a ticket-granting ticket TGT. It uses the TGT to request service tickets for resources outside the branch office.
There is no configuration required to use this feature. If you want to create access control based on claims and compound authentication, you need to deploy Dynamic Access Control. This requires that you upgrade to Kerberos clients and use the KDC, which support these new authorization types. With Windows Server , you do not have to wait until all the domain controllers and the domain functional level are upgraded to take advantage of new access control options.
The new KDC support for claims, compound authentication, and Kerberos armoring KDC administrative template policy setting allows you to configure a domain controller to support claims and compound authentication for Dynamic Access Control and Kerberos armoring by using Kerberos authentication. This policy setting is configured on the domain controller OU.
When the supported or higher setting is configured, domain controllers running Windows Server , Windows Server R2, or Windows Server will advertise domain support for claims and compound authentication for Dynamic Access Control and Kerberos armoring. No domain controllers running Windows Server can be in a domain that support claims and compound authentication for Dynamic Access Control and Kerberos armoring.
Additionally, the Kerberos client support for claims, compound authentication and Kerberos armoring administrative template policy setting enables you to configure devices running Windows 8 to support claims and compound authentication for Dynamic Access Control and Kerberos armoring by using Kerberos authentication.
Devices running Windows 8 will fail authentication if they cannot find a domain controller running Windows Server It is important to ensure that there are sufficient domain controllers running Windows Server for any account, referral, and resource domains that are supported.
The following table lists the four configurations that are available in KDC support for claims, compound authentication, and Kerberos armoring. All domain controllers advertise support for claims and compound authentication for Dynamic Access Control and Kerberos armoring. Requires sufficient domain controllers running Windows Server to handle the authentication requests for devices running Windows 8 in the domain.
Always provide claims and Fail unarmored authentication requests options cause intermittent authentication or access control failures if there are any domain controllers not running -Windows Server in the domain. So neither of these options will take effect until the domain is set at the Windows Server functional level. Until then, domain controllers running Windows Server will behave as if the Supported option is configured.
Supporting claims and compound authentication for Dynamic Access Control and Kerberos armoring will impact the domain controller because:. Secure Kerberos domain capability discovery is required, which results in additional message exchanges.
Resource servers running Windows Server send protocol transition requests for non-Windows 8 devices, which results in additional messages exchanges to account domains and referral domains. These requests will go outside the site when no domain controller is available in the site. Claims and compound authentication for Dynamic Access Control increases the size and complexity of the data in the message, which results in more processing time and greater Kerberos service ticket size.
Kerberos armoring fully encrypts Kerberos messages and signs Kerberos errors. This results in increased processing time, but it does not change the Kerberos service ticket size. Supporting claims and compound authentication for Dynamic Access Control and Kerberos armoring when the Supported option or higher is selected , could impact connectivity and file access because:. The setting configures a domain for the new access control model, which new services can choose to support.
Any device that supports claims, compound authentication, and Kerberos armoring cannot authenticate unless it can find a domain controller that supports claims, compound authentication and Kerberos armoring.
App meta-package is sufficient. Enable Windows authentication for IIS. Also enable anonymous access if usage of [AllowAnonymous] attribute is needed:. Enable authentication by adding the following to the Configure IApplicationBuilder app, Before we implement IClaimsTransformation a couple notes about it. First, they run on each AuthenticateAsync call, which means for IIS Authentication they may run only once and whatever claims we add to the collection are cached for as long as the user is logged in.
If we remove a logged in user from the list of administrators, they might continue to behave as such until they log in again. Second, they run on each AuthenticateAsync call, so we will heed this warning from the documentation of TransformAsync :. Note: this will be run on each AuthenticateAsync call, so its safer to return a new ClaimsPrincipal if your transformation is not idempotent. AD FS can be configured to act as either a claims provider or a relying party. The service issues tokens based on the claims information that it gets from an attribute store.
These attributes such as the user's name, email address, User Principal Name, role in the organization, group to which the user belongs, etc. AD FS can apply claims rules to incoming claims before producing outgoing claims based on them. Note that claims rules aren't shared across multiple trusts; they have to be created individually for each federated trust relationship. AD FS includes claim rule templates to make it easier for admins to create the rules.
As computing moves into the cloud both the private and public variety , identity takes on an even more important role at the same time that it increases in complexity. Microsoft has repeatedly renewed their vow of "all in" commitment to the cloud concept, so it makes sense that they also have focused on developing a strong identity solution for cloud based applications.
But that's not all - ACS can also enable those cloud based applications to accept the tokens issued by other cloud based identity providers such as Facebook, Google or Microsoft's own Windows Live ID.
In order to be a broad based identity provider, ACS supports a wide span of protocols and token formats. It issues and accepts SAML 1. The WS extensions are security standards by which web service requests are made. WS-Trust allows the exchange of security tokens for credentials in different trust domains. WS-Federation allows the relying party to control access based on the credibility of the claims validated by a different security realm.
These are custom identity providers that can be added to ACS. OpenID authentication is used by more than 50, web sites and over a billion users. It was first developed for use with Twitter.
Thus a user can log onto a social network, and then can authorize a web site to access specified data belonging to that user. ACS can get claims from a social network or email provider or some other identity provider and then pass those claims to another identity provider, which then issues a security token for access to applications that trust that second provider's STS.
The authentication was done by the social network or other provider from which ACS retrieved the claims. To do this, ACS redirects the user to the right identity provider to get authenticated, then sends a token to the relying party which in this case is a claims based application.
Of course, you might or might not want to trust Facebook as an identity provider. After all, the service doesn't really do much to vet the identities of users who sign up for accounts, beyond displaying a terms of service that requires the use of your real name, prohibits fake accounts, etc.
The good news is that you can configure ACS to accept authentication from those identity providers that you want to trust, and exclude those you don't trust. Users can select which of ACS's trusted providers they want to use to authenticate. Microsoft already has a widespread implementation of a rather simplified claims based identity service in the cloud: Windows Live ID.
Its claims based architecture was designed to work across different security boundaries and on different operating system platforms. Services can use Windows Live ID as a cloud based identity provider. The token is encrypted with the Windows Live ID public key. The identity library is the component that verifies whether a security token has a valid signature, determines by which STS the token was issued and verifies that the issuing STS is trusted by the application and assesses the claims that are contained in the token.
WIF is a framework with a set of APIs on which developers can build claims based applications relying parties. Here is more information about WIF. As we've explored in the earlier parts of this article, in the broad sense the systems we've been using for years to authenticate users such as Kerberos and NTLM are claims based in that the user names, passwords, roles and group memberships are forms of claims.
The "new" claims based identity platforms go much further, with the goal of removing the authentication burden from the "relying parties" - the individual applications and their developers and placing it on a trusted identity provider. This is not a new concept, either; Public Key Infrastructure works in the same basic way.
Why bother to establish a new standardized method of authenticating identities? But application developers often aren't security experts, and may not get that piece right. The beauty of a claims based system is that different authentication methods Kerberos, smart cards, forms, etc.
In classic-mode, SharePoint uses the Windows identity of the user directly. In claims-mode, SharePoint converts the Windows identity into a claims-based identity token that it can pass to other services as appropriate. Using claims-based authentication has several advantages over using Windows classic-mode authentication:.
App authentication and server-to-server authentication rely on claims-based authentication. If you use Windows classic-mode authentication, you will be unable to use external SharePoint apps.
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