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Extended Protection for Authentication with Reporting Services

 

Updated: August 26, 2016

Applies To: SQL Server 2016

Extended Protection is a set of enhancements to recent versions of the Microsoft 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 2016 Reporting Services 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.

System_CAPS_ICON_important.jpg Important


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 2016 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 Configure SSL Connections on a Native Mode Report Server

System_CAPS_ICON_important.jpg Important


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 2016 Reporting Services 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.

System_CAPS_ICON_important.jpg Important


Some data access technologies may not support extended protection. A data access technology is used to connect to SQL Server data sources and to the Reporting Services catalog database. Failure of a data access technology to support extended protection 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.

The documentation for a data access technology should have information about support for extended protection.

Upgrade

  • Upgrading a Reporting Services server to SQL Server 2016 adds configuration settings with default values to the rsreportserver.config file. If the settings were already present, the SQL Server 2016 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 2016 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 Reporting Services 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 Reporting Services 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.

ScenarioScenario DiagramHow to secure
Direct SSL communication.

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

1) Client application

2) Report server
Set RSWindowsExtendedProtectionLevel to Allow or Require.

Set RSWindowsExtendedProtectionScenario to Direct.

 

-Service Binding is not necessary because the SSL channel will be used for Channel Binding.
Direct HTTP communication. The report server will enforce Client to report server Service Binding.RS_ExtendedProtection_Direct

1) Client application

2) Report server
Set RSWindowsExtendedProtectionLevel to Allow or Require.

Set RSWindowsExtendedProtectionScenario to Any.

 

-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.

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.

ScenarioScenario DiagramHow to secure
HTTP communication. The report server will enforce client to report server Service Binding.RS_ExtendedProtection_Indirect

1) Client application

2) Report server

3) Proxy
Set RSWindowsExtendedProtectionLevel to Allow or Require.

Set RSWindowsExtendedProtectionScenario to Any.

 

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

-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_ExtendedProtection_Indirect_SSL

1) Client application

2) Report server

3) Proxy
Set
                    RSWindowsExtendedProtectionLevel to Allow or Require.

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

1) Client application

2) Report server

3) Proxy
Set
                    RSWindowsExtendedProtectionLevel to Allow or Require.

Set RSWindowsExtendedProtectionScenario to 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.

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.

ScenarioScenario DiagramHow to secure
Indirect HTTP communication.

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

1) Client application

2) Report server

3) Gateway device
Set RSWindowsExtendedProtectionLevel to Allow or Require.

Set RSWindowsExtendedProtectionScenario to Any.

 

-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.

-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.RS_ExtendedProtection_IndirectSSLandHTTPS

1) Client application

2) Report server

3) Gateway device
Set RSWindowsExtendedProtectionLevel to Allow or Require.

Set RSWindowsExtendedProtectionScenario to Direct.

 

-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.

-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.

ScenarioScenario DiagramHow 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.1) Client application

2) Report server

3) Proxy

4) Client application
Set RSWindowsExtendedProtectionLevel to Allow or Require.

Set RSWindowsExtendedProtectionScenario to Any.

 

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

1) Client application

2) Report server

3) Proxy

4) Client application
Set RSWindowsExtendedProtectionLevel to Allow or Require.

Set RSWindowsExtendedProtectionScenario to Proxy.

 

-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.

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.config 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.

SettingDescription
RSWindowsExtendedProtectionLevelSpecifies the degree of enforcement of extended protection. Valid values are:

 Off: Default. Specifies no channel binding or service binding verification.

 Allow supports extended protection but does not require it. 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.

 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.
RsWindowsExtendedProtectionScenarioSpecifies what forms of extended protection are validated: Channel binding, Service Binding, or both. Valid values are:

 Proxy: Default. Specifies:

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

-Service Binding is enforced.

 Any Specifies:

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

-Service binding is enforced.

 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.

 

Note: The RsWindowsExtendedProtectionScenario 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 sourceDescription
ComputerNameDnsDomainThe 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.
ComputerNameDnsFullyQualifiedThe 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.
ComputerNameDnsHostnameThe 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.
ComputerNameNetBIOSThe 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.
ComputerNamePhysicalDnsDomainThe 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.
ComputerNamePhysicalDnsFullyQualifiedThe 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.
ComputerNamePhysicalDnsHostnameThe 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.
ComputerNamePhysicalNetBIOSThe 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 Register a Service Principal Name (SPN) for a Report Server and About URL Reservations and Registration (SSRS Configuration Manager).

Connect to the Database Engine Using Extended Protection
Extended Protection for Authentication Overview
Integrated Windows Authentication with Extended Protection
Microsoft Security Advisory: Extended protection for authentication
Report Server Service Trace Log
RsReportServer.config Configuration File
SetExtendedProtectionSettings Method (WMI MSReportServer_ConfigurationSetting)

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