UNITED STATES PATENT APPLICATION FOR PROVIDING TOKENS TO ACCESS FEDERATED RESOURCES
CROSS-REFERENCE TO RELATED APPLICATION
[0001 ] This application claims the benefit of U.S. Provisional Patent
Application No. 60/634356 filed December 7, 2004, the contents of which are hereby incorporated by reference.
BACKGROUND
[0002] The invention relates generally to communication networks, and more
particularly to passive client single sign-on for Web applications.
[0003] In recent years, the Internet has become one of the most important
tools for organizations to communicate and interact with each other. Access to a
network resource by a user via the internet, or by a user in a related or federated
network, are increasing. Providing user directories to accommodate an expanded
group of users outside a typical network has tended to increase over time, along with
the effort in maintaining these directories. For security reasons, a user in a
particular organization often has to be authenticated before being granted access to
resources in another organization. Different mechanisms have been developed to
facilitate user authentication. One such mechanism is Web Services (WS) -
Federation. WS-Federation enables the sharing of identity across enterprise
boundaries using Extensible Markup Language (XML) security tokens. These XML
tokens utilize formats, such as Security Assertion Markup Language (SAML) or
Extensible Rights Markup Language (XrML).
[0004] Typically, the claims in the security tokens flow between a pair of
enterprises. However, for security reasons resources that a web client or a network
partner would access may be disposed outside of a security boundary. The
establishment of a security boundary may call for a shadow directory, and a token
transfer mechanism to preserve security. This arrangement typically calls for multiple
sign on by a user. In atypical token exchange the originator of the tokens is called
the Identity Provider. The Identity Provider owns a user's identity and authentication. The consumer of the tokens is called the Resource Provider. The Resource Provider may provide any number of Web Services or other applications. A cryptographic trust may be established between the two parties so that the Resource Provider can authenticate the Identity Provider as the authority for security tokens.
DESCRIPTION OF THE DRAWINGS
[0005] The present description will be better understood from the following
detailed description read in light of the accompanying drawings, wherein:
[0006] Tokens to Access Extranet Resources
[0007] FIG. 1 shows web single sign on as a part of a computer operating
system.
[0008] FIG. 2 shows various network examples implementing web SSO.
[0009] FIG. 3 is a block diagram showing system components used to
maintain security during Web SSO.
[0010] FIG. 4 is a block diagram showing overall processing flow for extranet
access.
[0011] FIG. 5 and FIG. 6 are flow diagrams showing a method of utilizing
tokens to access extranet resources.
[0012] Tokens to Access Federated Resources
[0013] FIG. 7 is a block diagram of overall processing flow for federated
partner to extranet resources
[0014] FIG. 8 is a flow diagram showing three different ways to map claims to
allow the generation of a NT access token that will allow access by a federation
partner.
[0015] Computing Environment
[0016] FIG. 9 illustrates an exemplary computing environment in which the
web SSO described in this application and network access by a federated partner,
may be implemented.
[0017] Like reference numerals are used to designate like parts in the
accompanying drawings.
DETAILED DESCRIPTION
[0018] The detailed description provided below in connection with the
appended drawings is intended as a description of the present examples and is not intended to represent the only forms in which the present example may be constructed or utilized. The description sets forth the functions of the example and the sequence of steps for constructing and operating the example. However, the same or equivalent functions and sequences may be accomplished by different examples.
[0019] Although the present examples are described and illustrated herein as
being implemented in an internet system, the system described is provided as an example and not a limitation. As those skilled in the art will appreciate, the present examples are suitable for application in a variety of different types of networked systems.
[0020] There are numerous existing web applications that have been built
and are currently used in corporate networks. Many of these applications use traditional Windows ™ authorization mechanisms to restrict access to the applications. At the application this means getting a Windows ™ token that includes Windows ™ Security Identifier ("SIDs") (user SIDs and group SIDs) such that access checks may be made with this token against Windows ™ based Access Control Lists ("ACLs") that use SIDs. There is a growing trend to move applications so that they are accessible from the internet, and from the networks of corporate partners, as opposed to access only from the corporate intranet. To minimize the burden of moving these applications, minimal modifications that allow Windows™ authorization to continue to be used are made. The first step in accomplishing this typically calls for moving an application into a DMZ that quarantines the associated network from access. Because of typical security restrictions placed on the DMZ it is typically not
ossible to use current Windows™ authentication mechanisms to build a Windows™
token at an application in the DMZ, unless extra shadow accounts are utilized.
[0021] A shadow account is an account that is shadowing a real corporate
user or partner account, for example a corporate employee has an account in the corporate network and would need an additional shadow account in the DMZ. Shadow accounts are typically provided to allow Windows™ authorization. Typically shadow accounts call for a substantial effort by an administrator to update and maintain.
[0022] Tokens are typically used to authenticate users. Active Directory
Federation Services ("ADFS") ™ is an example of an authentication system that provides ADFS tokens, for authentication and authorization to applications in a DMZ to exchange data. ADFS provides tokens that are different than Windows ™ tokens. Windows™ tokens that provide authorization are typically referred to as NT tokens. The examples provided may allow extranet, and federated access, and may allows Windows ™ tokens to be provided for applications running in the DMZ. The overall effect may be that the typical security measures, or restrictions typically utilized are not interfered with. A method of transferring security tokens is described in US Patent Application Number 10/993,745, filed November 19, 2004, and US Patent Application Number TBD (attorney docket number 312159.01), filed May 13, 2005, the contents of which are incorporated herein by reference.
[0023] The first example of Single sign-on ("SSO") may give a computer user
the ability to access various resources with a single identity, and with a single logon per session even when the user is accessing multiple applications. The first example may provide an ADFS token with additional authorization data, so that a Windows™ NT token may be constructed that will allow Windows™ authorization to be performed. Single sign on may allow the creation of NT tokens at the web agent in the absence of Active Directory accounts for users. Thus in the first example shadow accounts may be eliminated as authorization data is provided in the token. Web Single sign on ("WebSSO") is a subset of SSO that may apply only to browsable web
sites. Browsable web sites may well be regarded as the dominant form of SSO today due to the popularity of the Internet.
[0024] WebSSO designs may be configured to provide protocols and token
formats utilized by web services on the internet. A general description of the method is that for corporate accounts, SIDs from a corporate account forest are put into the ADFS token by a Federation Server ("FS") in the corporate network. Next, these SIDs are filtered by the FS in the DMZ, and then expanded by the ADFS web server agent at the Web Server (WS). The ADFS web server agent then builds a token from these SIDs. Note that the ADFS token is authenticated at each step along the way.
[0025] For the second example of federated partner access, or federated
resource sign on, federated partners also may need Windows ™ tokens in order to access these applications in the DMZ. Shadow accounts are typically required for conventional federated partners, since SIDs from a federated partner's Windows ™ forest would be useless in the resource DMZ. Typically the SIDS of one network are meaningless to another network. This second example may allow web servers to use traditional Windows based authorization for federated users without shadow accounts by constructing tokens that transfer account information from the active directory 305. The process used to build Windows ™ tokens for federated partners is described further below.
[0026] Furthermore, web SSO tends to facilitate identity and access
management capabilities of computer operating systems. For example the example of single sign on presented here tends to reduce the overhead associated with shadow accounts by eliminating them.
[0027] FIG. 1 shows single sign on 107, and federated resource sign on 108
as a part of a computer operating system 104. Computer operating systems 104 typically include a portion of their operating system that may facilitate networking 105. Of the networking functions 105 available, a single sign on ("SSO") 106 capability may be provided in the examples described below. Particularly a single
sign on ("web SSO") 107 that allows the elimination of shadow accounts, and a sign
on that allows access to federated resources that allow the elimination of shadow
accounts 108 will be described. The first example of Web SSO 107, may operate
independently of the second example of federated resource sign on 108.
[0028] Tokens to Access Extranet Resources
[0029] Web single sign on typically does not exist on a computer operating in
isolation. Web SSO may be provided on a plurality of processor based, or computing
devices 101, 102, 103 working in cooperation to form one or more networks.
Computing devices that make up a network typically include servers 103, PCs 102,
laptop computers 101 and the like. Any number of these computing devices may be
provided with web SSO capabilities so that they may operate in conjunction with one
or more client computers seeking to access a network providing SSO capabilities
while maintaining security and smooth operation of the network's functions. The
methods that allow access to federated resources may also be located in the
operating system 104. The federation access methods do not necessarily have to
reside in the same location as the SSO capabilities, and either may exist
independently of the other.
[0030] FIG. 2 shows various network examples implementing web SSO. In
implementing web SSO there are typically three network components (or players) that
may be of particular interest in SSO implementation. By deploying these components
in varying configurations various web SSO configurations may be possible.
[0031] First there may be a Web Clients (Users) 208-211 which may be the
program a user runs to access a web site. Examples include conventional
applications or browsers capable of accessing the internet.
[0032] The second component is the Web Site (Resource Owner) 212 which is
typically a service containing resources the user accesses. Examples may include
various applications, web pages, or web sites that a user may access. In a SSO
situation an organization such as a corporation may wish to deploy the web site 212
in the DMZ so that a client on the internet 210 may access the application. In the
present example the corporation may be able to move the application from the
intranet 203 to the DMZ 202, without reworking the application to change the
authorizations. However, moving an application to the DMZ has in the past involved providing a shadow account to establish trust through conventional authorization standards or access control lists..
[0033] Finally there is the Account Store (Account Administrator) 204-207
component which is typically a service that defines identities and attributes for controlling user access to web site resources. Examples may include LDAP-based directories, SQL-based databases, and the like. The resources may reside on the intranet 201, the DMZ 202 or the internet 218.
[0034] A system implementing web SSO provides flexibility when deploying
the three previously mentioned components to enable different WebSSO scenarios. Various configurations of these three components allow B2E 217, Federated B2B 214, Federated B2C 21 5, and Extranet 216 configurations. The first example of using tokens to access extranet resources is shown in the extranet configuration 216. The second example of using tokens to access federated resources is shown in the federated B2C 215 configuration and the federated B2B 214 configuration. The first and second examples will be described more fully below.
[0035] Business to Enterprise ("B2E") 217 typically allows employees from the
site's own business 211 to access the web site 212, using their employee identities from the business's account store 207. Employees can access the site from their intranet or out on the web without requiring a vpn. Federated business to business ("Federated B2B") 214 typically allows employees from a partner business208 to access the web site 212 using identities from their (partner business's) account store 204. Federated business to consumer ("Federated B2C") 21 5 typically allows consumers on the internet 209 access the web site 212 using identities from an external consumer account store (such as Passport) 205. B2B typically refers to e-commerce between different companies that have some sort of partnering arrangement, in contrast to B2C, or business-to-consumer, relationships in which individuals or companies purchase the products or services of another company. Extranets 216 typically allow consumers or ad hoc partners 210 to access the web
site 212 using accounts issued to them by the web site's business itself, and managed in an extranet account store 206 local to the site.
[0036] In each of these scenarios 214-21 7, the web site 212 effectively trusts
a different account store 204-207. The web site 212 trusts local account stores 206, 207 directly, and will trust partner or consumer account stores 204, 205 indirectly, via federation. Federated trusts typically require a business level agreement between two account store owners. Thus, one web site can mix and match configurations as shown.
[0037] Security is maintained in Web SSO configurations. WebSSO typically
provides the authentication and authorization infrastructure utilized by account
stores and web sites to implement the different trust scenarios presented by each
configuration in a safe way. In a B2E example 21 7, an employee 211 could access
internal and DMZ corporate web sites, as well as outsourced benefits sites, with a
single sign-on using her corporate Active Directory identity 207. In a B2B example
214, WebSSO could enable a first organization to federate a SharePoint site 206 in its
DMZ 202 with the employees of a second organization 208, using identities defined
and managed by the second organization within their own Active Directory 204.
[0038] Definitions of the terminology used above are provided in the
paragraphs that follow to aid the user in understanding the examples provided.
However these definitions are not meant to limit the practice of the examples to the
structures disclosed. It will be appreciated that the examples provided may be
applied to a variety of network configurations, and are not limited to any one
manufacturer's design, standard or particular implementation.
[0039] A federation typically refers to the association of different
organizations (e.g., different autonomous identity domains or realms) that have employed agreements, standards, and/or cooperative technologies to make user identity and entitlements portable between the organizations. In this manner, a user of one realm can access a Web application of a different realm without multiple logon events.
[0040] A forest may be used to link more closely related organizations.
Domains are often used to represent organizations and their members. A tree is typically a collection of domains, or child domains. To manage closely related business entities, such as within a corporation, each respective tree ("tree") can be interconnected within a domain forest ("forest"). Trees in a forest are typically connected by two way trust relationships. When trees are grouped together and implemented as a network system in a forest, the forest boundary becomes the trust (e.g., security) boundary and the unit of administrative isolation for the group of domains.
[0041] A demilitarized zone ("DMZ") may refer to a perimeter security
network typically established at a boundary between a local area network ("LAN") and the internet. Such a DMZ serves to protect servers on the LAN from malicious users on the internet. Typically a firewall stands between the LAN and DMZ. A DMZ may include proxy servers, web servers, and virtual private network ("VPN") servers. Proxy servers typically provide secure access for external users accessing information on the LAN, and typically appear transparent to client computers. Proxy servers may be programmed to disallow access to specific resources. Web servers are typically accessible to anyone on the internet. VPN servers are typically remote access and authentication servers that allow secure access to the LAN through the internet. Secure access to network may be provided by various security protocols such as a conventional Kerberos system. Security protocols are protocols that allow networks and systems to authenticate users, computers, and applications for purposes of accessing resources on these networks and systems. Security protocols use various forms of encryption to ensure the privacy, authenticity, and integrity of a user's credentials and of network communications.
[0042] FIG. 3 is a block diagram showing system components typically used
to maintain security during Web SSO that uses tokens to access extranet resources and allows shadow directories to be omitted. Web SSO may maintain security by providing the following components.
[0043] First, Security Token Service Proxies for the Active Directory 301 are
provided. These services produce web-appropriate security tokens for identities and attributes contained in Active Directory 305. The Active Directory 305 stays in the intranet 31 3, protected by proxied services 309 in the DMZ 314. A web server ("WS") 320 is deployed in the DMZ to make applications available to a client or web client, 311. Deploying the WS in the DMZ typically calls for deploying the FSR 309 in the DMZ so that trust is established between the WS and FSR without causing security issues by crossing the DMZ, Intranet boundary. FSP-A 321 is the proxy server of FS A 308.
[0044] Second, Federation Services for Managing Web Site Trust 302 gives
resource owners the mechanism to define and control trust with the various account store owners. Federation Services are described in US Patent No. 09/886,146, filed June 20, 2001 and US Patent Number 10/029,426, filed December 21, 2001, the contents of which are incorporated by reference.
[0045] Third, SSO Agents Process Security Tokens for Web Applications 303.
- These agents (ISAPI extension and token/claims libraries) may convert security tokens into a Windows ™ NT (Microsoft Corporation Trademark) Impersonation context or ASP.Net roles utilized by IIS applications for access control. In alternative embodiments equivalent agents that process security tokens may be substituted. Security claims are described in further detail in US Patent Application Number 11/119,236 filed April 29, 2005the contents of which are incorporated herein by reference.
[0046] Fourth, an Interoperable Web Services Protocol, or passive client
protocol 304 is provided. Account stores and web sites typically do not communicate directly; security tokens are conveyed between them by clients using protocols such as the Web Services-Federation passive client protocol. This type of protocol exchanges Web Services-Security XML security tokens, including SAML and XrML tokens. Alternatively other equivalent protocols and token exchanges may be utilized. An exemplary interoperable web services protocol is described in US Patent
No. 10/436,880, filed May 1 2, 2003, the contents of which are incorporated by
reference.
[0047] Fifth a Web Server, including a plurality of applications is provided.
The web server typically trusts the server FSR, 309.
[0048] Web Single Sign On ("SSO") may give a user the ability to access
computer resources with a single identity, and a single logon per session, even when
accessing multiple applications. Web single sign on ("WebSSO") is typically regarded
as a subset of single sign on that applies only to browsable web sites. However due
to the popularity of the internet web single sign on tends to be more prevalent than
SSO.
[0049] A network may provide a DMZ zone outside of its firewall. Resources
may be deployed in this DMZ zone. In accordance with an illustrative embodiment,
corporate users access DMZ resources using traditional Windows ™ authentication &
authorization using single sign on without shadow accounts. In this scenario, a
company has a DMZ zone where the company deploys resources (for example,
SharePomt servers) accessible to corporate users.
[0050] FIG. 4 is a block diagram showing overall processing flow for extranet
access. The extranet DMZ active directory ("AD") 404 has a one way Windows ™ trust
to the corpnet active directory 402. A LogonSever/FederationServer ("LS-R/FS-R")
403 is deployed in the Extranet Resource realm and a LogonSever/FederationServer
("LS-A/FS-A") 404 is deployed in the Corpnet Account realm or intranet 401.
Federation trust between the Extranet Resource realm and the Corpnet Account
realm is flagged on both sides as the "WindowsRealmTrust" trust which means that
the Extranet realm has applications using traditional Windows ™ authentication and
authorization for users from the Corpnet realm AD store. The trusting application
running on the web server ("WS") is flagged as "WindowsRealmTrust" on federation
server ("FS-R") which means that the application is accepting user SIDs for the
purposes of building the local NT access token.
[0051] The client accesses a traditional web application running on the web
server, WS, deployed in the DMZ. The client may be located on the Internet or on the
intranet. The end goal is to build an NT access token on WS so that normal NT
authorization can be used against access control lists ("ACLs") on the accessed
resources. This means that the user authorization attributes (SIDs) will be delivered
to WS in some form.
[0052] FIG. 5 and FIG. 6 are flow diagrams showing a method of utilizing
tokens to access extranet resources by a client on the internet. The flow of token
exchanges for establishing Windows™ trust is maintained as is typical for a
Windows™ network, or its equivalent. However, the construction and content of the
tokens are varied by providing security identifiers ("SIDs") in the token instead of in a
shadow account. For authentication the SIDs are already present and there is no need
for an application to retrieve them from a shadow account in the application's
domain.
[0053] First the client on the internet accesses (via HTTP GET) the resource
URL from the web client having the desired application, that is located in the DMZ
501. The client has no authentication cookie, so the client is redirected to LS-R/FS-
R. Second, the LS-R determines the client home realm and redirects the client to LS-
A-EXT 502.
[0054] If the client is located on the corpnet, the client sends the request to
LS-A rather than LS-A-EXT. There are a few options for this implementation. For
example, a special DNS configuration can be used on the corpnet DNS servers so that
the LS-A-EXT name gets resolved to the IP address of LS-A. Another possibility
executed in an alternative embodiment is to have two NICs on LS-A-EXT (one NIC
facing the corpnet and the other one facing the Internet) and determine the client
locality based on which NIC is used to connect to LS-A-EXT. In this case, LS-A uses
integrated authentication which provides FS-A with all user SIDs.
[0055] Or, if the client is located on the Internet, LS-A-EXT collects the user
credentials (username&password or the client certificate) and sends them to FS-A for
credential validation or verification 503. FS-A validates the user credentials. After
credentials are validated, FS-A has a collection of user SIDs from the local NT access
token 504.
[0056] With the user SIDs obtained in the previous step, FS-A transforms the
SIDs into Group claims and obtains Custom claims using LDAP attributes from the
user AD account 505. Then, given that the resource realm is WindowsRealmTrust,
FS-A obtains account group SIDs for the user 506. Then FS-A issues a SAML token
carrying the transformed WebSSO claims as attributes and account group SIDs within
the Advice element 507. For further details see the section "SID Packing" for the
format of the Advice element. FS-A passes the SAML token in-proc to LS-A (case 3a)
or sends the token back to LS-A-EXT (case 3b) 508. LS-A/LS-A-EXT writes the SAML
token as a cookie to the client and redirects the client to LS-R/FS-R 509.
[0057] FS-R receives the SAML token and validates it 510. Upon successful
token validation, FS-R performs normal claim transformation for the claims obtained
from the token. Then, given that the account realm is the WindowsRealmTrust
realm, FS-R processes the user SIDs from the SAML Advice element 511. Specifically,
FS-R filters the received SIDs (as described in the section "SID Filtering" below). FS-R
issues a SAML token to WS carrying transformed claims appropriate to WS as
attributes and filtered account group SIDs within the Advice element 512.
Continuing the flow diagram in FIG. 6, FS-R returns control to LS-R which writes the
generated SAML token as a cookie to the client and redirects the client to WS 613.
[0058] The WebSSO ISAPI extension on WS receives the token and redirects to
the original URL 614 that the client was trying to access. In this redirect the ISAPI
extension writes the WebSSO token as a cookie.
[0059] The WebSSO ISAPI extension on WS receives the token as a cookie and
passes it to the WebSSO service for validation 61 5. The service validates the token,
obtains SIDs, and passes the SIDs to the WebSSO authentication package 616. The
package expands the SIDs to add resource group SIDs for the domain WS is joined to
61 7 (see the section "Group Expansion" below). The resulting collection of SIDs is
used to build an NT access token 618. Blocks 61 5-61 8 show that for security
reasons a NT service and an LSA Authentication Package are used to verify the
WebSSO token and then turn the SIDs from that token into an NT access token 619.
The SID collection is cached in the authentication package and keyed with the hash
of the incoming account SIDs 620 for future use. The NT access token handle is cached in the WebSSO ISAPI extension and keyed with the hash of the SAML token for future use 621.
[0060] Cookies written to the client are used to achieving single sign-on
experience and to avoiding repetitive and typically expensive operations. The cookie
written in 508 (of FIG. 5) will be used when the client is redirected from the resource
realm to the account realm, so that the user credentials verification and claim/SID
extraction can be avoided. The cookie written in 510 (of FIG. 5) will be used when
the client is redirected by a resource application server to the resource realm FS-R,
so that claim transformation and SID filtering can be avoided. The cookie written in
614 will be used as the client communicates with WS as follows.
[0061 ] The WebSSO ISAPI extension will search the cached NT token in its
cache (by hashing the SAML token sent in the cookie and finding corresponding
cache entry with that hash), so the user will immediately be impersonated. If no
cached NT token is found, the WebSSO ISAPI extension will pass SIDs from the cookie
to the WebSSO authentication package that will search its cache to find an entry with
the key equal to the hash of the incoming SIDs, so that the resource group SID
expansion can be avoided. If the WebSSO authentication package does not find the
SIDs in its cache then it will build a NT access token as specified in 61 5 -621 above.
[0062] An alternative example of the resource group expansion process
would be to expand groups on FS-R instead of WS. This way, FS-R would write a cookie to the client with all the SIDs and use the SIDs next time the client accesses some other resource provided the other resource is joined to the same domain as WS. However, this would call for knowledge on FS-R of the domains for all deployed application servers. One way to achieve this is to include the domain name as part of wctx parameter prepared on the application and sent to FS-R. This parameter is not be authenticated, so WS could put a domain name other than the one WS is joined to.
[0063] A further alternative example is to configure the domain of WS in the
trust policy at the time the trusting application is added, but this approach would typically call for more administration Credentials Verification
[0064] The following description expands upon the credential verification
process described above at step 503 (of FIG. 5). In this process, FS-A verifies two types of user credentials: Username and password, and the client cert. The username and password are verified via the published LogonUser API. The result is an NT access token that typically contains all user SIDs (account SIDs and resource SIDs for the domain FS-A is joined to). The username maybe in the UPN format (user@somewhere.com) or in the SAM account name format (somewhere\user). The client cert will typically be verified by passing it to the WebSSO authentication package via a LsaCallAuthenticationPackage call with the protocol submit buffer containing the cert in the following data structure:
(STRUCTURE REMOVED)

[0065] The call will typically be allowed from an untrusted caller so that FS-A
doesn't have to hold the TCB privilege. However, since the package is returning the user security attributes, the package may allow the call only if the caller is FS. To this end, the FS setup will typically create a local machine group ADFSGroup and put the FS account into that group. The auth package will verify that the caller has the ADFSGroup SID in its NT access token.
[0066] The WebSSO package will in turn pass the cert to the Windows
TLS/SSL Security Service Provider™ for verification via the internal LsalCalI Package call. Upon successful verification, the WebSSO package will return the user UPN, the
user account domain name, and the user token groups (SIDs) in the following data strucf
(STRUCTURE REMOVED)

[0067] Group Expansion
[0068] The following description expands upon the credential verification
process described above at step 61 7. FS-A performs the account and resource
group expansions by using new AuthZ functionality implemented for that purpose,
AuthziWebSsoGetGroupsBySid. AuthZ currently does group expansion, but the
expansion is not selective, i.e. both account and resource groups were always
expanded. AuthZ has been modified so that the expansions are separated so that
the account side (FS-A) can expand the account groups and the resource side (WS)
can expand the resource groups in their respective domains. In addition,
performance optimizations are implemented to cache LDAP and SAM handles used
by AuthZ.
[0069] SID Packing
[0070] To reduce the size of the SAML token, SIDs are packed in the SAML
(STRUCTURE REMOVED)

[0071 ] (Note that "http://fabrikam.com/federation/vl /Windowsldentifiers" is
a temporary namespace.) The Windowsldentifiers element contains base64 encoded string containing the user SIDs in the following format:
[0072] Flags | DomainSidCount | AccountDomainSid | RidCount | Rid_l | ... |
Rid_N | DomainSid | RidCount | Rid_l | .. | Rid_M | ...
[0073] Here the vertical separator | indicates the DWORD boundary. The first
DWORD is the Flags parameter. If bit 1 is set in the Flags parameter received by WS,
it will indicate that WS needs to expand the groups to add the resource groups. The
second DWORD is the parameter that indicates how many domain SIDs are present in
the buffer. The next DWORD is the first domain SID which is the account domain
SID. The next DWORD is the number of RIDs for the account domain SID. Note that
account and group SIDs are constructed by combining the domain SID with the
corresponding RIDs. The next DWORD is the RID of the user account. It is followed
by the group RIDs (of which there will be one less than the number defined in the
RidCount). Then there comes the next domain SID followed by the RID count for that
domain followed by the RIDs. The pattern repeats itself until all domain SIDs with
their RIDs are enumerated.
[0074] SID Filtering
[0075] WebSSO performs SID filtering on FS-R that follows the same rules as
the native SID filtering typically performed on resource domain controllers. Filtering
is achieved using the typical Windows ™ implementation and implementing the
internal DC specific Windows Local Security Authority ("LSA") (not to be confused with
LS-A) routines. Those routines compute the domain and forest trust topologies and
perform SID searches at runtime. To implement them domain trusts and the forest
trusts from the root domain DC are obtained by using DsEnumerateDomainTrusts
and DsGetForestTrustlnformationW APIs. These APIs return information needed to
determine the trust boundaries and identify the trust types and trust attributes of the
extranet trust. Given that information, any given SID may be matched against the
domain SIDs in the local forest, as well as trusted domains (trusted either directly or
transitively for cross forest trusts). That information is updated periodically to
account for domain trust changes. This allows implementation of the internal LSA
APIs used so that the same core code base may be used. The final section of this
document will deal with the federated partner access to these resources.
[0076] Tokens to Access Federated Resources
[0077] FIG. 7 is a block diagram of overall processing flow for federated
partner to extranet resources. The extranet DMZ Active Directory includes shadow
accounts in the Active Directory that Web SSO tokens may be mapped to, so that a
NT access token may be generated. The protocol to get the Web SSO token is similar
to the protocol described above and the WS-Federation protocol. Once the FS-R has
the Web SSO token for the client issued by the account FS then the FS-R may map
the claims in that token.
[0078] FIG. 8 is a flow diagram showing three different ways to map claims to
allow the generation of a NT access token.
[0079] First the User Principal Name ("UPN") claim is in the FS-A issued token
801 and this claim is passed through by the FS-R unchanged to the WS 802. In this
case it is assumed that there is a shadow account in the DMZ AD that has UPN that
matches the federated client's UPN claim.
[0080] Second the e-mail claim is in the FS-A issued token 803 and the claim
is changed to a UPN claim 804. The claim is passed through by the FS-R to the WS
805. In this case it is assumed that there is a shadow account in the DMZ AD that
has a UPN that matches the federated client's email address.
[0081] And third a group claim is in the FS-A issued token 806, and is
mapped to a UPN claim 807. In this case it is assumed that there is a shadow
account in the DMZ AD that has a UPN that matches the mapping UPN. Note that
multiple client's are mapped to one shadow account in this case.
[0082] Currently the only place where shadow accounts are required is on the
resource side of a federated relationship that deploys traditional (NT access token
based) applications. Shadow accounts are typically required so that the ADFS web
agent can impersonate the shadow account for the purposes of building the NT
access token. Shadow accounts, are typically a major customer concern due to the
need to deploy the accounts and maintain them. In many cases, shadow accounts
constitute deployment blockers as is currently the case for deploying ADFS in the
DMZ).
[0083] This second example may remove shadow accounts by transforming
inbound group claims received from a non-DMZ account realm into local resource
AD groups and use the AD group SIDs to build the NT token. The resources will be
ACL'ed with local AD group SIDs, therefore the resulting NT token will be appropriate
for access checks performed by the resource application.
[0084] To implement this second example, that may eliminate shadow
directories, a new corporate group claim type, ActiveDirectoryGroupClaim is utilized. Claims are typically statements that an authority may make about principals, such as name, identity, key, group, privilege, capability and the like. Claims may be asserted by security tokens.
[0085] This claim type extends the GroupClaim by adding a SID property
which is the SID of the corresponding AD group. ActiveDirectoryGroupClaim is a
GroupClaim and it will, therefore, be treated as such in typically all places that
currently manipulate corporate group claims like claim transformations.
[0086] At runtime, after the resource FS-R gets an inbound token from a
non-DMZ realm and transforms inbound group claims into outbound corporate group claims (which may include AD groups) issued to the application, FS-R will typically add the AD group SID for each ActiveDirectoryGroupClaim found in the outbound collection.
[0087] In addition to the group SIDs, the FS will typically generate the user
SID derived from the trusted realm URI and the value of the identity claim in the
inbound token (see below for the details of the user SID generation algorithm).
[0088] The resulting user SID and the group SIDs will be passed to the web
server agent in the Advice element of the new token issued, which is typically the
same way as it's done conventionally by the DMZ resource FS-R.
[0089] The web server (WS) will get the SIDs, will expand them to add
resource domain local group SIDs, and will build the token with these SIDs via a conventional authentication package. To build the NT token, in addition to SIDs the auth package may need to have the AuthenticatingAuthority and the AccountName properties that are set as the originating account authority and the user name in the resulting logon session, respectively. The account realm URI and the identity claim value may be used for this purpose, respectively.
[0090] Note that as a result, the account realm URI and the user identity will
be logged in the security audit event generated by the LSA upon successful logon performed by the authorization package. This tends to be a useful feature as it provides auditing capabilities for the actual user account instead of a shadow account.
[0091] An example of such audit is shown below; the audit was generated
upon a successful logon of user user@adatum.com by our auth package modified as described above.
(STRUCTURE REMOVED)

[0092] In a further alternative examples a customer may deploy shadow
accounts for some users and use the SAML-group-to-AD-group transformation (SG2ADC) for other users. In principle, for a given set of UPN/Email and SIDs, one may first attempt to do a shadow account logon and, if the shadow account logon fails with error indicating that the user doesn't exist, do the logon with SIDs. However, doing this typically impacts perf significantly in cases when shadow accounts are not deployed for many users.
[0093] To determine whether to use shadow accounts or SIDs, a new trust
policy OM enumeration type, ShadowAccountExistence, for trusted realms is added.
The enum will typically have four values: Unspecified, ShadowAccountsAbsent,
ShadowAccountsForSomeUsers, ShadowAccountsForAIIUsers. Unspecified means
that the shadow account existence has not been specified for users from this realm.
This is the default value. ShadowAccountsAbsent means that there are no shadow
accounts deployed for users coming from this trusted realm. In that case, SIDs
resulting from the SG2ADG transforms will be used to build the NT token.
ShadowAccountsForSomeUsers typically means that shadow accounts are deployed
for some users from this trusted realm. In this case, logon with shadow accounts
UPN/Email will be attempted first and then logon with SIDs will be attempted next for
users from this trusted realm. ShadowAccountsForAIIUsers typically means that
shadow accounts are deployed for all users from this trusted realm. Only logon with
shadow account UPN/Email will be attempted in this case.
[0094] At the runtime, when FS-R issues a SAML token to a traditional
application, FS-R will indicate in the issued SAML token the type of the logon the
application should perform. FS-R will determine the type of logon based on the
value of ShadowAccountExistence as follows.
[0095] Unspecified: if the resulting claim collection contains
ActiveDirectoryGroupClaim claims, FS-R will indicate that only logon with SIDs
should be attempted. Otherwise, if the user identity is UPN/Email, FS-R will indicate
that only shadow account logon should be attempted. Otherwise, FS-R will fail the
user request because the traditional WS will not be able to build the NT token.
[0096] ShadowAccountsAbsent: if the resulting claim collection contains
ActiveDirectoryGroupClaim claims, FS-R will indicate that logon with SIDs should be
attempted. Otherwise, FS-R will fail the user request because the traditional WS will
not be able to build the NT token.
[0097] ShadowAccountsForSomeUsers: if the user identity is UPN/Email, FS-R
will indicate that the shadow account logon should be attempted first, and then the
SIDs logon should be attempted next if SIDs are present in the SAML token issued to
the application. Otherwise, if the resulting claim collection contains
ActiveDirectoryCroupClaim claims, FS-R will indicate that logon with SIDs should be
attempted. Otherwise, FS-R will fail the user request because the traditional WS will
not be able to build the NT token.
[0098] ShadowAccountsForAIIUsers: if the user identity is UPN/Email, FS-R
will indicate that the shadow account logon should be attempted for the user; FS-R
will not include SIDs in the SAML token. Otherwise, FS-R will fail the user request
even if the resulting claim collection contains ActiveDirectoryGroupClaim claims.
Indeed, ActiveDirectoryGroupClaim claims may appear in the collection in the sense
of normal GroupClaim and it's not admin's intention to treat them as AD groups per
the value of ShadowAccountsForAIIUsers.
[0099] ' The presence of the packed SIDs structure in the SAML token
issued to WS will indicate that WS should attempt the SIDs logon. The structure will
also indicate whether shadow account logon should be attempted prior to the SIDs
logon. Specifically, if bit 2 is set in the Flags parameter of the structure, WS will first
attempt shadow account logon using UPN/Email identity claim from the SAML token.
Otherwise, WS will do SIDs logon only. If the SID structure is absent, WS will do the
shadow account logon only.
[00100] The Ul will typically support setting the value of the
ShadowAccountExistence enumeration type for trusted non-DMZ realms. The Ul will
also support the new ActiveDirectoryGroupClaim claim type in the organization
claims. The only difference between the new claim type and the existing group claim
type is the addition of the Sid attribute which will be populated via the same Object
Picker code that is already implemented in the Ul for the group claim population by
the AD store.
[00101 ] User SID generation
[00102] The FS will generate the user SID as follows. The SID will be unique
for a given user from a given trusted realm. The SID will typically be 28 bytes long
(which is the size of a normal AD SID). The SID_IDENTIFIER_AUTHORITY of the SID
will typically be set to a new ADFS authority to distinguish the SID from any other
existing SIDs. The 20 bytes allocated to SID sub-authorities will be filled with the hash of the string "\" where is the URI of the account realm that issued the SAML token and is the value of the identity claim (UPN, Email, or CommonName) from the SAML token. The 20 byte hash will typically be large enough to generate unique SID for a given user from a given realm. So, to summarize, the generated SID will typically look like "S-1 --<5 DWORD sub-authorities filled with the 20 byte hash>".
[00103] Note that the WebSSO token issued to the federated client will not
have SIDs in the Advice element. The WS then receives the WebSSO token, as a
cookie, issued by the FS-R with a UPN claim. The WebSSO token is verified by the NT
service and the UPN is passed to an LSA authentication package. If the WS is in a
Windows ™ 2003 (Microsoft Trademark ™ domain where Kerberos S4U is supported
then the service will call the Kerberos authentication package with LsaLogonUser and
an NT token will be returned. If the WS is in a Windows 2000 ™ domain then the
WebSSO Authentication package is called, using LsaLogonUser, and the UPN is
passed in to the package and a token is returned. The WebSSO Authentication
package uses the AuthZ APIs to get the SIDs for the passed in UPN and then builds a
token based on these SIDs.
[00104] The structures used when calling LsaLogonUser are
(STRUCTURE REMOVED)

[00105] The client application, in this case the service, calls
LsaLookupAuthenticationPackage with the package name ("WebSsoAp") and then calls LsaLogonUser and provides a filled—in _WEBSSO_LOGON structure in the AuthlnfoBuffer parameter.
[00106] The authentication package maintains an AVL-tree based cache of the
token information retrieved from AzMan, index on the client UPN.
[00107] Computing Environment
[00108] FIG. 9 illustrates an exemplary computing environment 900 in which
the web SSO described in this application, may be implemented. Exemplary computing environment 900 is only one example of a computing system and is not intended to limit the examples described in this application to this particular computing environment.
[00109] For example the computing environment 900 can be implemented
with numerous other general purpose or special purpose computing system configurations. Examples of well known computing systems, may include, but are not limited to, personal computers, hand-held or laptop devices, microprocessor-based systems, multiprocessor systems, set top boxes, gaming consoles, consumer electronics, cellular telephones, PDAs, and the like.
[00110] The computer 900 includes a general-purpose computing system in
the form of a computing device 901. The components of computing device 901 can include one or more processors (including CPUs, GPUs, microprocessors and the like) 907, a system memory 909, and a system bus 908 that couples the various system components. Processor 907 processes various computer executable instructions, including those to control the operation of computing device 901 and to communicate with other electronic and computing devices (not shown). The system bus 908 represents any number of several types of bus structures, including a
memory bus or memory controller, a peripheral bus, an accelerated graphics port,
and a processor or local bus using any of a variety of bus architectures.
[00111] The system memory 909 includes computer-readable media in the
form of volatile memory, such as random access memory (RAM), and/or non-volatile memory, such as read only memory (ROM). A basic input/output system (BIOS) is stored in ROM. RAM typically contains data and/or program modules that are immediately accessible to and/or presently operated on by one or more of the processors 907.
[00112] Mass storage devices 904 may be coupled to the computing device
901 or incorporated into the computing device by coupling to the buss. Such mass
storage devices 904 may include a magnetic disk drive which reads from and writes
to a removable, non volatile magnetic disk (e.g., a "floppy disk") 905, or an optical
disk drive that reads from and/or writes to a removable, non-volatile optical disk
such as a CD ROM or the like 906. Computer readable media 905, 906 typically
embody computer readable instructions, data structures, program modules and the
like supplied on floppy disks, CDs, portable memory sticks and the like.
[00113] Any number of program modules can be stored on the hard disk 910,
Mass storage device 904, ROM and/or RAM 909, including by way of example, an operating system, one or more application programs, other program modules, and program data. Each of such operating system, application programs, other program modules and program data (or some combination thereof) may include an embodiment of the systems and methods described herein.
[00114] A display device 902 can be connected to the system bus 908 via an
interface, such as a video adapter 911. A user can interface with computing device 702 via any number of different input devices 903 such as a keyboard, pointing device, joystick, game pad, serial port, and/or the like. These and other input devices are connected to the processors 907 via input/output interfaces 912 that are coupled to the system bus 908, but may be connected by other interface and bus structures, such as a parallel port, game port, and/or a universal serial bus (USB).
[0011 5] Computing device 900 can operate in a networked environment using
connections to one or more remote computers through one or more local area
networks (LANs), wide area networks (WANs) and the like. The computing device
901 is connected to a network 914 via a network adapter 913 or alternatively by a
modem, DSL, ISDN interface or the like. K
[00116] Those skilled in the art will realize that storage devices utilized to
store program instructions can be distributed across a network. For example a remote computer may store an example of the process described as software. A local or terminal computer may access the remote computer and download a part or all of the software to run the program. Alternatively the local computer may download pieces of the software as needed, or distributively process by executing some software instructions at the local terminal and some at the remote computer (or computer network). Those skilled in the art will also realize that by utilizing conventional techniques known to those skilled in the art that all, or a portion of the software instructions may be carried out by a dedicated circuit, such as a DSP, programmable logic array, or the like.

CLAIMS
1. A system for authenticating computer users comprising:
a single active directory disposed in a federated partner;
a web server disposed in a DMZ associated with the intranet; and
a client disposed in the federated partner coupled to the web server through
an internet connection that is capable of signing on to the web server.