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Extended Protection for Authentication with Reporting Services

Extended Protection is a set of enhancements to recent versions of the Windows operating system. Extended protection enhances how credentials and authentication can be protected by applications. The feature itself does not directly provide protection against specific attacks such as credential forwarding, but it provides an infrastructure for applications such as Reporting Services to enforce Extended Protection for Authentication.

The main authentication enhancements that are part of extended protection are service binding and channel binding. Channel binding uses a channel binding token (CBT), to verify that the channel established between two end points was not compromised. Service binding uses Service Principal Names (SPN) to validate the intended destination of authentication tokens. For more background information about extended protection, see Integrated Windows Authentication with Extended Protection.

SQL Server 2008 R2 supports and enforces Extended Protection that has been enabled in the operating system and configured in Reporting Services. By default, Reporting Services accepts requests that specify Negotiate or NTLM authentication and could therefore benefit from Extended Protection support in the operating system and the Reporting Services extended protection features.

Important noteImportant

By default, Windows does not enable Extended Protection. For information about how to enable Extended Protection in Windows, see Extended Protection for Authentication. Both the operating system and client authentication stack must support Extended Protection so that authentication succeeds. For older operating systems you may need to install more than one update for a complete, Extended Protection ready computer. For information on recent developments with Extended Protection, see updated information with Extended Protection.

SQL Server 2008 R2 Reporting Services supports and enforces extended protection that has been enabled in the operating system. If the operating system does not support extended protection or the feature in the operating system has not been enabled, the Reporting Services extended protection feature will fail authentication. Reporting Services Extended Protection also requires an SSL Certificate. For more information, see Configuring a Report Server for Secure Sockets Layer (SSL) Connections

Important noteImportant

By default, Reporting Services does not enable Extended Protection. The feature can be enabled by modifying the rsreportserver.config configuration file or using WMI APIs to update the configuration file. SQL Server 2008 R2 does not provide a user interface to modify or view extended protection settings. For more information, see the configuration settings section in this topic.

Common issues that occur because of changes in extended protection settings or incorrectly configured settings are not be exposed with obvious error messages or dialog windows. Issues related to extended protection configuration and compatibility result in authentication failures and errors in the Reporting Services trace logs. For information about troubleshooting and verifying extended protection with Reporting Services, see Troubleshooting Extended Protection (Reporting Services)

Important noteImportant

Microsoft SQL Client has not been updated to support extended protection at the time of the SQL Server 2008 R2 release. SQL Client is used to connect to SQL Server data sources and to the Reporting Services catalog database. This limitation in SQL Client impacts Reporting Services in the following ways:

The SQL Server that runs the Reporting Services catalog database cannot have extended protection enabled or the report server will not successfully connect to the catalog database and return authentication errors.

SQL Servers that are used as Reporting Services report data sources cannot have extended protection enabled or tries by the report server to connect to the report data source will fail and return authentication errors. A possible work around is to change the Reporting Services data sources to use native providers, and not SQL Client. For example, configure the data sources for the ODBC driver and then the SQL Native Client will be used, which does support Extended Protection.

Upgrade

  • Upgrading an Reporting Services server to SQL Server 2008 R2 adds configuration settings with default values to the rsreportserver.config file. If the settings were already present, the SQL Server 2008 R2 installation will preserve them in the rsreportserver.config file.

  • When the configuration settings are added to the rsreportserver.config configuration file, the default behavior is for the Reporting Services extended protection feature to be off and you must enable the feature as described in this topic. For more information, see the configuration settings section in this topic.

  • The default value for the setting RSWindowsExtendedProtectionLevel is Off.

  • The default value for the setting RSWindowsExtendedProtectionScenario is Proxy.

  • SQL Server 2008 R2 Upgrade Advisor does not verify that the operating system or the current installation of Reporting Services has Extended Protection support enabled.

What Reporting Services extended protection does not cover

The following feature areas and scenarios are not supported by the extended protection feature:

  • Authors of Reporting Services custom security extensions must add support for extended protection to their custom security extension.

  • Third-party components added to or used by a installation must be updated by the third-party vendor, to support extended protection. For more information, contact the third-party vendor.

The following scenarios illustrate different deployments and topologies and the recommended configuration to secure them with Reporting Services Extended Protection.

Direct

This scenario describes directly connecting to a report server, for example, an intranet environment.

Scenario

Scenario Diagram

How to secure

Direct SSL communication.

The report server will enforce client to report server Channel Binding.

Extended Protection Direct access with SSL

1) Client application

2) Report server

  • Service Binding is not necessary because the SSL channel will be used for Channel Binding.

Set RSWindowsExtendedProtectionLevel to Allow or Require.

Set RSWindowsExtendedProtectionScenario to Direct.

Direct HTTP communication. The report server will enforce Client to report server Service Binding.

Extended Protection and direct access

1) Client application

2) Report server

  • There is no SSL Channel therefore no enforcement of Channel Binding is possible.

  • Service Binding can be validated, however, it is not a complete defense without Channel binding and Service Binding on its own will only protect from basic threats.

Set RSWindowsExtendedProtectionLevel to Allow or Require.

Set RSWindowsExtendedProtectionScenario to Any.

Proxy and Network Load Balancing

Client applications connect to a device or software that performs SSL and passes through the credentials to the server for authentication, for example, an extranet, Internet, or Secure Intranet. The client connects to a Proxy or all clients use a proxy.

The situation is the same when you are using a Network Load Balancing (NLB) device.

Scenario

Scenario Diagram

How to secure

HTTP communication. The report server will enforce client to report server Service Binding.

RS Extended Protection Indirect access

1) Client application

2) Report server

3) Proxy

  • There is no SSL Channel therefore no enforcement of Channel Binding is possible.

Set RSWindowsExtendedProtectionLevel to Allow or Require.

Set RSWindowsExtendedProtectionScenario to Any.

  • The report server must be configured to know the name of the proxy server to make sure that the service binding is correctly enforced.

HTTP communication.

The report server will enforce client to Proxy Channel Binding and client to report server Service Binding.

RS Extended Protection Indirect Access with SSL

1) Client application

2) Report server

3) Proxy

  • SSL channel to proxy is available therefore channel binding to the proxy can be enforced.

  • Service Binding can also be enforced.

  • The Proxy name must be known to the report server and the report server administrator should either create a URL reservation for it, with a host header or configure the Proxy name in the Windows registry entry BackConnectionHostNames.

RSWindowsExtendedProtectionLevel to Allow or Require.

Set RSWindowsExtendedProtectionScenario to Proxy.

Indirect HTTPS communication with a secure proxy. Report server will enforce client to proxy Channel Binding and Client to report server Service Binding.

Extended Protection Indirect access SSL and HTTPS

1) Client application

2) Report server

3) Proxy

  • SSL channel to proxy is available therefore channel binding to the proxy can be enforced.

  • Service Binding can also be enforced.

  • The Proxy name must be known to the report server and the report server administrator should either create a URL reservation for it, with a host header or configure the Proxy name in the Windows registry entry BackConnectionHostNames.

RSWindowsExtendedProtectionLevel to Allow or Require.

Set RSWindowsExtendedProtectionScenario to Proxy.

Gateway

This scenario describes Client applications connecting to a device or software that performs SSL and authenticates the user. Then the device or software impersonates the user context or a different user context before it makes a request to the report server.

Scenario

Scenario Diagram

How to secure

Indirect HTTP communication.

Gateway will enforce Client to Gateway channel binding. There is a Gateway to report server Service Binding.

RS Extended Protection Indirect Access with SSL

1) Client application

2) Report server

3) Gateway device

  • Channel Binding from client to report server is not possible because the gateway impersonates a context and therefore creates a new NTLM token.

  • There is no SSL from the Gateway to report server therefore channel binding cannot be enforced.

  • Service Binding can be enforced.

Set RSWindowsExtendedProtectionLevel to Allow or Require.

Set RSWindowsExtendedProtectionScenario to Any.

  • The Gateway device should be configured by your administrator to enforce channel binding.

Indirect HTTPS communication with a Secure Gateway. The Gateway will enforce Client to Gateway Channel Binding and the report server will enforce Gateway to report server Channel Binding.

Extended Protection Indirect access SSL and HTTPS

1) Client application

2) Report server

3) Gateway device

  • Channel Binding from client to report server is not possible because the gateway impersonates a context and therefore creates a new NTLM token.

  • SSL from Gateway to the report sever means channel binding can be enforced.

  • Service Binding is not required.

Set RSWindowsExtendedProtectionLevel to Allow or Require.

Set RSWindowsExtendedProtectionScenario to Direct.

  • The Gateway device should be configured by your administrator to enforce channel binding.

Combination

This scenario describes Extranet or Internet environments where the client connects a Proxy. This is in combination with an intranet environment where a client connects to report server.

Scenario

Scenario Diagram

How to secure

Indirect and direct access from client to report server service without SSL on either of the client to proxy or client to report sever connections.

Extended Protection mixed environment

1) Client application

2) Report server

3) Proxy

4) Client application

  • Service Binding from client to report server can be enforced.

  • The Proxy name must be known to the report server and the report server administrator should either create a URL reservation for it, with a host header or configure the Proxy name in the Windows registry entry BackConnectionHostNames.

Set RSWindowsExtendedProtectionLevel to Allow or Require.

Set RSWindowsExtendedProtectionScenario to Any.

Indirect and direct access from client to report server where the client establishes an SSL connection to the proxy or report server.

Extended Protection mixed with SSL

1) Client application

2) Report server

3) Proxy

4) Client application

  • Channel Binding can be used

  • The Proxy name must be known to the report server and the report server administrator should either create a URL reservation for the proxy, with a host header or configure the Proxy name in the Windows registry entry BackConnectionHostNames.

Set RSWindowsExtendedProtectionLevel to Allow or Require.

Set RSWindowsExtendedProtectionScenario to Proxy.

The rsreportserver.config file contains the configuration values that control the behavior of Reporting Services extended protection.

For more information on using and editing the rsreportserver.config file, see RSReportServer Configuration File. The extended protection settings can also be changed and inspected using WMI APIs. For more information, see SetExtendedProtectionSettings Method (WMI MSReportServer_ConfigurationSetting).

When validation of the configuration settings fail, the authentication types RSWindowsNTLM, RSWindowsKerberos and RSWindowsNegotiate are disabled on the report server.

Configuration Settings for reporting services extended protection

The following table provides information about configuration settings that appear in the rsreportserver.config for extended protection.

Setting

Description

RSWindowsExtendedProtectionLevel

Specifies the degree of enforcement of extended protection. Valid values are Off, Allow, and Require.

The default value is Off.

The value Off specifies no channel binding or service binding verification.

The value Allow supports extended protection but does not require it. The value Allow specifies:

  • Extended protection will be enforced for client applications that are running on operating systems that support extended protection. How protection is enforced is determined by setting RsWindowsExtendedProtectionScenario.

  • Authentication will be allowed for applications that are running on operating systems which do not support extended protection.

The value Require specifies:

  • Extended protection will be enforced for client applications that are running on operating systems that support extended protection.

  • Authentication will not be allowed for applications that are running on operating systems which do not support extended protection.

RsWindowsExtendedProtectionScenario

Specifies what forms of extended protection are validated: Channel binding, Service Binding, or both. Valid values are Any, Proxy, and Direct.

The default value is Proxy.

The value Any specifies:

  • Windows NTLM, Kerberos, and Negotiate authentication and a channel binding are not required.

  • Service binding is enforced.

The value Proxy specifies:

  • Windows NTLM, Kerberos, and Negotiate authentication when a channel binding token is present.

  • Service Binding is enforced.

The value Direct specifies:

  • Windows NTLM, Kerberos, and Negotiate authentication when a CBT is present, an SSL connection to the current service is present, and the CBT for the SSL connection matches the CBT of the NTLM, Kerberos or negotiate token.

  • Service Binding is not enforced.

NoteNote
This setting is ignored if RsWindowsExtendedProtectionLevel is set to OFF.

Example entries in the rsreportserver.config configuration file:

<Authentication>
         <RSWindowsExtendedProtectionLevel>Allow</RSWindowsExtendedProtectionLevel>
         <RSWindowsExtendedProtectionScenario>Proxy</RSWindowsExtendedProtectionLevel>
</Authentication>

Service binding uses Service Principal Names or SPN to validate the intended destination of authentication tokens. Reporting Services uses the existing URL reservation information to build a list of SPNs that are considered valid. Using the URL reservation information for validation of both SPN and URL reservations enables system administrators to manage both from a single location.

The list of valid SPNs is updated when the report server starts, the configuration settings for extended protection are changed, or when the application domain is recycled.

The valid list of SPNs is specific for each application. For example, Report Manager and Report Server will each have a different list of valid SPNs calculated.

The list of valid SPNs calculated for an application is determined by the following factors:

  • Each URL reservation.

  • Each SPN retrieved from the domain controller for the reporting services service account.

  • If a URL reservation includes wildcard characters ('*' or '+'), then Report Server will add each entry from the hosts collection.

Hosts collection sources.

The following table lists the potential sources for the Hosts collection.

Type of source

Description

ComputerNameDnsDomain

The name of the DNS domain assigned to the local computer. If the local computer is a node in a cluster, the DNS domain name of the cluster virtual server is used.

ComputerNameDnsFullyQualified

The fully qualified DNS name that uniquely identifies the local computer. This name is a combination of the DNS host name and the DNS domain name, using the form HostName.DomainName. If the local computer is a node in a cluster, the fully qualified DNS name of the cluster virtual server is used.

ComputerNameDnsHostname

The DNS host name of the local computer. If the local computer is a node in a cluster, the DNS host name of the cluster virtual server is used.

ComputerNameNetBIOS

The NetBIOS name of the local computer. If the local computer is a node in a cluster, the NetBIOS name of the cluster virtual server is used.

ComputerNamePhysicalDnsDomain

The name of the DNS domain assigned to the local computer. If the local computer is a node in a cluster, the DNS domain name of the local computer is used, not the name of the cluster virtual server.

ComputerNamePhysicalDnsFullyQualified

The fully qualified DNS name that uniquely identifies the computer. If the local computer is a node in a cluster, the fully qualified DNS name of the local computer, is used not the name of the cluster virtual server.

The fully qualified DNS name is a combination of the DNS host name and the DNS domain name, using the form HostName.DomainName.

ComputerNamePhysicalDnsHostname

The DNS host name of the local computer. If the local computer is a node in a cluster, the DNS host name of the local computer is used, not the name of the cluster virtual server.

ComputerNamePhysicalNetBIOS

The NetBIOS name of the local computer. If the local computer is a node in a cluster, the NetBIOS name of the local computer, not the name of the cluster virtual server.

As SPNs are added, an entry is added to the trace log that resembles the following:

rshost!rshost!10a8!01/07/2010-19:29:38:: i INFO: SPN Whitelist Added <ComputerNamePhysicalNetBIOS> - <theservername>.

rshost!rshost!10a8!01/07/2010-19:29:38:: i INFO: SPN Whitelist Added <ComputerNamePhysicalDnsHostname> - <theservername>.

For more information, see How to: Register a Service Principal Name (SPN) for a Report Server and About URL Reservations and Registration (Reporting Services).

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