Overview

The integration between the CAS Server and ADFS delegates user authentication from CAS Server to ADFS, making CAS Server a WS-Federation client. Claims released from ADFS are made available as attributes to CAS Server, and by extension CAS Clients.

:warning: Deprecated

WS-Federation support is deprecated and is scheduled for removal in a future CAS version.

:information_source: Remember

The functionality described here allows CAS to use ADFS as an external identity provider. If you wish to do the opposite, allowing ADFS to become a CAS client and using CAS as an identity provider, you may take advantage of SAML2 support in CAS as one integration option.

Support is enabled by including the following dependency in the WAR overlay:

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<dependency>
    <groupId>org.apereo.cas</groupId>
    <artifactId>cas-server-support-wsfederation-webflow</artifactId>
    <version>${cas.version}</version>
</dependency>
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implementation "org.apereo.cas:cas-server-support-wsfederation-webflow:${project.'cas.version'}"
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dependencyManagement {
    imports {
        mavenBom "org.apereo.cas:cas-server-support-bom:${project.'cas.version'}"
    }
}

dependencies {
    implementation "org.apereo.cas:cas-server-support-wsfederation-webflow"
}
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dependencies {
    /*
        The following platform references are included automatically and are listed for reference only.

        implementation enforcedPlatform("org.apereo.cas:cas-server-support-bom:${project.'cas.version'}")
        implementation platform(org.springframework.boot.gradle.plugin.SpringBootPlugin.BOM_COORDINATES)
        
    */
    implementation "org.apereo.cas:cas-server-support-wsfederation-webflow"
}

You may also need to declare the following repository in your CAS Overlay to be able to resolve dependencies:

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repositories {
    maven { 
        mavenContent { releasesOnly() }
        url "https://build.shibboleth.net/maven/releases/" 
    }
}
:information_source: JCE Requirement

It's safe to make sure you have the proper JCE bundle installed in your Java environment that is used by CAS, especially if you need to consume encrypted payloads issued by ADFS. Be sure to pick the right version of the JCE for your Java version. Java versions can be detected via the java -version command.

WsFed Configuration

Adjust and provide settings for the ADFS instance, and make sure you have obtained the ADFS signing certificate and made it available to CAS at a location that can be resolved at runtime.

The following settings and properties are available from the CAS configuration catalog:

cas.authn.wsfed[0].attribute-mutator-script.locationPath to attribute mutator groovy script that allows one to modify wsfed attributes before establishing a final principal.
no default
Required

Path to attribute mutator groovy script that allows one to modify wsfed attributes before establishing a final principal. The location of the resource. Resources can be URLs, or files found either on the classpath or outside somewhere in the file system.

In the event the configured resource is a Groovy script, especially if the script is set to reload on changes, you may need to adjust the total number of inotify instances. On Linux, you may need to add the following line to /etc/sysctl.conf: fs.inotify.max_user_instances = 256.

You can check the current value via cat /proc/sys/fs/inotify/max_user_instances.

In situations and scenarios where CAS is able to automatically watch the underlying resource for changes and detect updates and modifications dynamically, you may be able to specify the following setting as either an environment variable or system property with a value of false to disable the resource watcher: org.apereo.cas.util.io.PathWatcherService.

Type
Resource
Default
none
Defined by
SpringResourceProperties
cas.authn.wsfed[0].cookie.crypto.encryption.keyThe encryption key is a string whose length is defined by the encryption key size setting.
no default
RequiredSpEL

The encryption key is a string whose length is defined by the encryption key size setting.

Type
String
Default
none
Defined by
EncryptionJwtCryptoProperties
Supports
Spring Expression Language
cas.authn.wsfed[0].cookie.crypto.signing.keyThe signing key is a string whose length is defined by the signing key size setting.
no default
RequiredSpEL

The signing key is a string whose length is defined by the signing key size setting.

Type
String
Default
none
Defined by
SigningJwtCryptoProperties
Supports
Spring Expression Language
cas.authn.wsfed[0].idInternal identifier for this wsfed configuration.
no default
Required

Internal identifier for this wsfed configuration. If undefined, the identifier would be auto-generated by CAS itself. In the event that there is more than on CAS server defined in a clustered deployment, this identifier must be statically defined in the configuration.

Type
String
Default
none
Defined by
WsFederationDelegationProperties
cas.authn.wsfed[0].identity-attributeThe attribute extracted from the assertion and used to construct the CAS principal id.
upn
Required

The attribute extracted from the assertion and used to construct the CAS principal id.

Type
String
Default
upn
Defined by
WsFederationDelegationProperties
cas.authn.wsfed[0].identity-provider-identifierThe entity id or the identifier of the Wsfed instance.
http://adfs.example.org/adfs/services/trust
RequiredSpEL

The entity id or the identifier of the Wsfed instance.

Type
String
Default
http://adfs.example.org/adfs/services/trust
Defined by
WsFederationDelegationProperties
Supports
Spring Expression Language
cas.authn.wsfed[0].identity-provider-urlWsfed identity provider url.
https://adfs.example.org/adfs/ls/
RequiredSpEL

Wsfed identity provider url.

Type
String
Default
https://adfs.example.org/adfs/ls/
Defined by
WsFederationDelegationProperties
Supports
Spring Expression Language
cas.authn.wsfed[0].principal.principal-transformation.groovy.locationTransform usernames using a Groovy resource.
no default
Required

Transform usernames using a Groovy resource. The location of the resource. Resources can be URLs, or files found either on the classpath or outside somewhere in the file system.

In the event the configured resource is a Groovy script, especially if the script is set to reload on changes, you may need to adjust the total number of inotify instances. On Linux, you may need to add the following line to /etc/sysctl.conf: fs.inotify.max_user_instances = 256.

You can check the current value via cat /proc/sys/fs/inotify/max_user_instances.

In situations and scenarios where CAS is able to automatically watch the underlying resource for changes and detect updates and modifications dynamically, you may be able to specify the following setting as either an environment variable or system property with a value of false to disable the resource watcher: org.apereo.cas.util.io.PathWatcherService.

Type
Resource
Default
none
Defined by
SpringResourceProperties
cas.authn.wsfed[0].relying-party-identifierThe identifier for CAS (RP) registered with wsfed.
urn:cas:localhost
RequiredSpEL

The identifier for CAS (RP) registered with wsfed.

Type
String
Default
urn:cas:localhost
Defined by
WsFederationDelegationProperties
Supports
Spring Expression Language
cas.authn.wsfed[0].signing-certificate-resourcesLocations of signing certificates used to verify assertions.
classpath:adfs-signing.crt
Required

Locations of signing certificates used to verify assertions. Locations could be specified as static file-system resources(certificates) or they could also be federation XML metadata, either as a URL or an XML file. If federation metadata XML is provided, the signing certificate is extracted from the IDPSSODescriptor's key descriptor that is marked for signing.

Type
String
Default
classpath:adfs-signing.crt
Defined by
WsFederationDelegationProperties
cas.authn.wsfed[0].attribute-resolver-enabledWhether CAS should enable its own attribute resolution machinery after having received a response from wsfed.
true

Whether CAS should enable its own attribute resolution machinery after having received a response from wsfed.

Type
boolean
Default
true
Defined by
WsFederationDelegationProperties
cas.authn.wsfed[0].attributes-typeIndicates how attributes should be recorded into the principal object.
WSFED

Indicates how attributes should be recorded into the principal object. Useful if you wish to additionally resolve attributes on top of what wsfed provides. Accepted values are CAS,WSFED,BOTH.

Type
String
Default
WSFED
Defined by
WsFederationDelegationProperties
cas.authn.wsfed[0].auto-redirect-typeWhether CAS should auto redirect to this wsfed instance.
SERVER
Whether CAS should auto redirect to this wsfed instance. Available values are as follows:
  • SERVER: Redirect on the server side, typically making CAS invisible.
  • CLIENT: Redirect on the client side using browser redirects, etc.
  • NONE: Do nothing and let the selection take place manually.
Type
DelegationAutoRedirectTypes
Default
SERVER
Defined by
WsFederationDelegationProperties
cas.authn.wsfed[0].cookie.allowed-ip-addresses-patternA regular expression pattern that indicates the set of allowed IP addresses, when #isPinToSession() is configured.
no default
Regex

A regular expression pattern that indicates the set of allowed IP addresses, when #isPinToSession() is configured. In the event that there is a mismatch between the cookie IP address and the current request-provided IP address (i.e. network switches, VPN, etc), the cookie can still be considered valid if the new IP address matches the pattern specified here.

Type
String
Default
none
Defined by
WsFederationDelegatedCookieProperties
cas.authn.wsfed[0].cookie.crypto.algThe signing/encryption algorithm to use.
A256CBC-HS512

The signing/encryption algorithm to use.

Type
String
Default
A256CBC-HS512
Defined by
EncryptionJwtSigningJwtCryptographyProperties
cas.authn.wsfed[0].cookie.crypto.enabledWhether crypto operations are enabled.
true

Whether crypto operations are enabled.

Type
boolean
Default
true
Defined by
EncryptionJwtSigningJwtCryptographyProperties
cas.authn.wsfed[0].cookie.crypto.encryption.key-sizeThe encryption key size.
512

The encryption key size.

Type
int
Default
512
Defined by
EncryptionJwtCryptoProperties
cas.authn.wsfed[0].cookie.crypto.signing.key-sizeThe signing key size.
512

The signing key size.

Type
int
Default
512
Defined by
SigningJwtCryptoProperties
cas.authn.wsfed[0].cookie.crypto.strategy-typeControl the cipher sequence of operations.
ENCRYPT_AND_SIGN
Control the cipher sequence of operations. The accepted values are:
  • ENCRYPT_AND_SIGN: Encrypt the value first, and then sign.
  • SIGN_AND_ENCRYPT: Sign the value first, and then encrypt.
Type
String
Default
ENCRYPT_AND_SIGN
Defined by
EncryptionJwtSigningJwtCryptographyProperties
cas.authn.wsfed[0].cookie.domainCookie domain.
no default

Cookie domain. Specifies the domain within which this cookie should be presented. The form of the domain name is specified by RFC 2965. A domain name begins with a dot (.foo.com) and means that the cookie is visible to servers in a specified Domain Name System (DNS) zone (for example, www.foo.com, but not a.b.foo.com). By default, cookies are only returned to the server that sent them.

Type
String
Default
none
Defined by
WsFederationDelegatedCookieProperties
cas.authn.wsfed[0].cookie.geo-locate-client-sessionWhen set to true and assuming #isPinToSession() is also true , client sessions (using the client IP address) are geo-located using a geolocation service when/if configured.
no default

When set to true and assuming #isPinToSession() is also true, client sessions (using the client IP address) are geo-located using a geolocation service when/if configured. The resulting session is either pinned to the client geolocation, or the default client address.

Type
boolean
Default
none
Defined by
WsFederationDelegatedCookieProperties
cas.authn.wsfed[0].cookie.http-onlytrue if this cookie contains the HttpOnly attribute.
true

true if this cookie contains the HttpOnly attribute. This means that the cookie should not be accessible to scripting engines, like javascript.

Type
boolean
Default
true
Defined by
WsFederationDelegatedCookieProperties
cas.authn.wsfed[0].cookie.max-ageThe maximum age of the cookie, specified in seconds.
-1
Duration

The maximum age of the cookie, specified in seconds. By default, -1 indicating the cookie will persist until browser shutdown. A positive value indicates that the cookie will expire after that many seconds have passed. Note that the value is the maximum age when the cookie will expire, not the cookie's current age. A negative value means that the cookie is not stored persistently and will be deleted when the Web browser exits. A zero value causes the cookie to be deleted.

Type
String
Default
-1
Defined by
WsFederationDelegatedCookieProperties
cas.authn.wsfed[0].cookie.nameCookie name.
no default

Cookie name. Constructs a cookie with a specified name and value. The name must conform to RFC 2965. That means it can contain only ASCII alphanumeric characters and cannot contain commas, semicolons, or white space or begin with a $ character. The cookie's name cannot be changed after creation. By default, cookies are created according to the RFC 2965 cookie specification. Cookie names are automatically calculated assigned by CAS at runtime, and there is usually no need to customize the name or assign it a different value unless a special use case warrants the change.

Type
String
Default
none
Defined by
WsFederationDelegatedCookieProperties
cas.authn.wsfed[0].cookie.pathCookie path.
no default

Cookie path. Specifies a path for the cookie to which the client should return the cookie. The cookie is visible to all the pages in the directory you specify, and all the pages in that directory's subdirectories. A cookie's path must include the servlet that set the cookie, for example, /catalog, which makes the cookie visible to all directories on the server under /catalog. Consult RFC 2965 (available on the Internet) for more information on setting path names for cookies.

Type
String
Default
none
Defined by
WsFederationDelegatedCookieProperties
cas.authn.wsfed[0].cookie.pin-to-sessionWhen generating cookie values, determine whether the value should be compounded and signed with the properties of the current session, such as IP address, user-agent, etc.
true

When generating cookie values, determine whether the value should be compounded and signed with the properties of the current session, such as IP address, user-agent, etc.

Turning off session pinning is not exactly ideal. This is a barrier to prevent cookie replay attacks. A cookie that was created with an IP given a certain location cannot be replayed back in a different browser with a different IP from a different location.

There may however be legitimate reasons to turn it off and relax this after careful reviews, if you intend to support a type of user who intends to switch their IP quite frequently. A classic example is the type of user that is on VPN at the time of login, but decides to resume their work a few hours later off VPN or at a different location.

Type
boolean
Default
true
Defined by
WsFederationDelegatedCookieProperties
cas.authn.wsfed[0].cookie.same-site-policyIf a cookie is only intended to be accessed in a first party context, the developer has the option to apply one of settings SameSite=Lax or SameSite=Strict or SameSite=None to prevent external access.
no default

If a cookie is only intended to be accessed in a first party context, the developer has the option to apply one of settings SameSite=Lax or SameSite=Strict or SameSite=None to prevent external access.

To safeguard more websites and their users, the new secure-by-default model assumes all cookies should be protected from external access unless otherwise specified. Developers must use a new cookie setting, SameSite=None, to designate cookies for cross-site access. When the SameSite=None attribute is present, an additional Secure attribute is used so cross-site cookies can only be accessed over HTTPS connections.

Accepted values are:
  • Lax
  • Strict
  • None
  • Off: Disable the generation of the SameSite cookie attribute altogether.
  • Path to a Groovy script that is able to generate the SameSite cookie attribute dynamically.
  • Fully qualified name of a class that implements org.apereo.cas.web.cookie.CookieSameSitePolicy
Type
String
Default
none
Defined by
WsFederationDelegatedCookieProperties
cas.authn.wsfed[0].cookie.secureTrue if sending this cookie should be restricted to a secure protocol, or false if the it can be sent using any protocol.
true

True if sending this cookie should be restricted to a secure protocol, or false if the it can be sent using any protocol.

Type
boolean
Default
true
Defined by
WsFederationDelegatedCookieProperties
cas.authn.wsfed[0].encryption-certificateThe path to the public key/certificate used to handle and verify encrypted assertions.
classpath:certificate.crt

The path to the public key/certificate used to handle and verify encrypted assertions.

Type
String
Default
classpath:certificate.crt
Defined by
WsFederationDelegationProperties
cas.authn.wsfed[0].encryption-private-keyThe path to the private key used to handle and verify encrypted assertions.
classpath:private.key

The path to the private key used to handle and verify encrypted assertions.

Type
String
Default
classpath:private.key
Defined by
WsFederationDelegationProperties
cas.authn.wsfed[0].encryption-private-key-passwordThe private key password.
NONE

The private key password.

Type
String
Default
NONE
Defined by
WsFederationDelegationProperties
cas.authn.wsfed[0].nameName of the authentication handler.
no default

Name of the authentication handler.

Type
String
Default
none
Defined by
WsFederationDelegationProperties
cas.authn.wsfed[0].orderThe order of the authentication handler in the chain.
2147483647

The order of the authentication handler in the chain.

Type
int
Default
2147483647
Defined by
WsFederationDelegationProperties
cas.authn.wsfed[0].principal.active-attribute-repository-idsActivated attribute repository identifiers that should be used for fetching attributes if attribute resolution is enabled.
*

Activated attribute repository identifiers that should be used for fetching attributes if attribute resolution is enabled. The list here may include identifiers separated by comma.

Type
String
Default
*
Defined by
PersonDirectoryPrincipalResolverProperties
cas.authn.wsfed[0].principal.attribute-repository-selectionControl the behavior of the attribute repository selection by authentication method or handler.
no default

Control the behavior of the attribute repository selection by authentication method or handler. The map here is keyed by the authentication handler name, and the value is the attribute repository identifiers separated by comma. When the authentication handler is executed, the attribute repositories assigned to this handler will be selected to fetch attributes. Note that the resolution engine will always favor attribute repositories assigned to the service definition, if any and as part of its authentication policy, over this global setting.

Type
Map<String, String>
Default
none
Defined by
PersonDirectoryPrincipalResolverProperties
cas.authn.wsfed[0].principal.attribute-resolution-enabledWhether attribute repositories should be contacted to fetch person attributes.
UNDEFINED
Whether attribute repositories should be contacted to fetch person attributes. Defaults to true if not set. Available values are as follows:
  • TRUE: Constant to represent the true state.
  • FALSE: Constant to represent the false state.
  • UNDEFINED: Constant to represent the undefined state.
Type
TriStateBoolean
Default
UNDEFINED
Defined by
PersonDirectoryPrincipalResolverProperties
cas.authn.wsfed[0].principal.principal-attributeAttribute name to use to indicate the identifier of the principal constructed.
no default

Attribute name to use to indicate the identifier of the principal constructed. If the attribute is blank or has no values, the default principal id will be used determined by the underlying authentication engine. The principal id attribute usually is removed from the collection of attributes collected, though this behavior depends on the schematics of the underlying authentication strategy.

Type
String
Default
none
Defined by
PersonDirectoryPrincipalResolverProperties
cas.authn.wsfed[0].principal.principal-resolution-conflict-strategyIn the event that the principal resolution engine resolves more than one principal, (especially if such principals in the chain have different identifiers), this setting determines strategy by which the principal id w...
last

In the event that the principal resolution engine resolves more than one principal, (especially if such principals in the chain have different identifiers), this setting determines strategy by which the principal id would be chosen from the chain. Accepted values are: last, first.

Type
String
Default
last
Defined by
PersonDirectoryPrincipalResolverProperties
cas.authn.wsfed[0].principal.principal-resolution-failure-fatalWhen true, throws an error back indicating that principal resolution has failed and no principal can be found based on the authentication requirements.
UNDEFINED
When true, throws an error back indicating that principal resolution has failed and no principal can be found based on the authentication requirements. Otherwise, logs the condition as an error without raising a catastrophic error. Available values are as follows:
  • TRUE: Constant to represent the true state.
  • FALSE: Constant to represent the false state.
  • UNDEFINED: Constant to represent the undefined state.
Type
TriStateBoolean
Default
UNDEFINED
Defined by
PersonDirectoryPrincipalResolverProperties
cas.authn.wsfed[0].principal.principal-transformation.blocking-patternA regular expression that will be used against the username to match for blocking/forbidden values.
no default
SpEL

A regular expression that will be used against the username to match for blocking/forbidden values. If a match is found, an exception will be thrown and principal transformation will fail.

Type
String
Default
none
Defined by
PrincipalTransformationProperties
Supports
Spring Expression Language
cas.authn.wsfed[0].principal.principal-transformation.case-conversionIndicate whether the principal identifier should be transformed into upper-case, lower-case, etc.
NONE
Indicate whether the principal identifier should be transformed into upper-case, lower-case, etc. Available values are as follows:
  • NONE: No conversion.
  • LOWERCASE: Lowercase conversion.
  • UPPERCASE: Uppercase conversion.
Type
PrincipalTransformationProperties.CaseConversion
Default
NONE
Defined by
PrincipalTransformationProperties
cas.authn.wsfed[0].principal.principal-transformation.patternA regular expression that will be used against the provided username for username extractions.
no default
SpEL

A regular expression that will be used against the provided username for username extractions. On a successful match, the first matched group in the pattern will be used as the extracted username.

Type
String
Default
none
Defined by
PrincipalTransformationProperties
Supports
Spring Expression Language
cas.authn.wsfed[0].principal.principal-transformation.prefixPrefix to add to the principal id prior to authentication.
no default
SpEL

Prefix to add to the principal id prior to authentication.

Type
String
Default
none
Defined by
PrincipalTransformationProperties
Supports
Spring Expression Language
cas.authn.wsfed[0].principal.principal-transformation.suffixSuffix to add to the principal id prior to authentication.
no default
SpEL

Suffix to add to the principal id prior to authentication.

Type
String
Default
none
Defined by
PrincipalTransformationProperties
Supports
Spring Expression Language
cas.authn.wsfed[0].principal.return-nullReturn a null principal object if no attributes can be found for the principal.
UNDEFINED
Return a null principal object if no attributes can be found for the principal. Available values are as follows:
  • TRUE: Constant to represent the true state.
  • FALSE: Constant to represent the false state.
  • UNDEFINED: Constant to represent the undefined state.
Type
TriStateBoolean
Default
UNDEFINED
Defined by
PersonDirectoryPrincipalResolverProperties
cas.authn.wsfed[0].principal.use-existing-principal-idUses an existing principal id that may have already been established in order to run person directory queries.
UNDEFINED
Uses an existing principal id that may have already been established in order to run person directory queries. This is generally useful in situations where authentication is delegated to an external identity provider and a principal is first established to then query an attribute source. Available values are as follows:
  • TRUE: Constant to represent the true state.
  • FALSE: Constant to represent the false state.
  • UNDEFINED: Constant to represent the undefined state.
Type
TriStateBoolean
Default
UNDEFINED
Defined by
PersonDirectoryPrincipalResolverProperties
cas.authn.wsfed[0].toleranceTolerance value used to skew assertions to support clock drift.
PT10S
Duration

Tolerance value used to skew assertions to support clock drift.

Type
String
Default
PT10S
Defined by
WsFederationDelegationProperties

Required settings may be needed to activate or affect the feature; review them even when they have a default. Optional settings only need to be set to change a default or to turn on the behavior they control. Third party settings belong to libraries such as Spring Boot that CAS builds on; their own documentation may have more detail.

Signing & encryption

This CAS feature is able to accept signing and encryption crypto keys. In most scenarios if keys are not provided, CAS will auto-generate them. The following instructions apply if you wish to manually and beforehand create the signing and encryption keys.

Note that if you are asked to create a JWK of a certain size for the key, you are to use the following set of commands to generate the token:

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wget https://raw.githubusercontent.com/apereo/cas/master/etc/jwk-gen.jar
java -jar jwk-gen.jar -t oct -s [size]

The outcome would be similar to:

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{
  "kty": "oct",
  "kid": "...",
  "k": "..."
}

The generated value for k needs to be assigned to the relevant CAS settings. Note that keys generated via the above algorithm are processed by CAS using the Advanced Encryption Standard (AES) algorithm which is a specification for the encryption of electronic data established by the U.S. National Institute of Standards and Technology.


Groovy scripting

CAS takes advantage of Apache Groovy in forms of either embedded or external scripts that allow one to, by default, dynamically build constructs, attributes, access strategies and a lot more. To activate the functionality described here, you may need to prepare CAS to support and integrate with Apache Groovy.

Please review this guide to configure your build.

Principal transformation

Authentication handlers that generally deal with username-password credentials can be configured to transform the user id prior to executing the authentication sequence. Each authentication strategy in CAS provides settings to properly transform the principal. Refer to the relevant settings for the authentication strategy at hand to learn more.

Authentication handlers as part of principal transformation may also be provided a path to a Groovy script to transform the provided username. The outline of the script may take on the following form:

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String run(final Object... args) {
    def (providedUsername,logger) = args
    return providedUsername.concat("SomethingElse")
}

To prepare CAS to support and integrate with Apache Groovy, please review this guide.

Notes on configuration

Configuration Metadata

The collection of configuration properties listed in this section are automatically generated from the CAS source and components that contain the actual field definitions, types, descriptions, modules, etc. This metadata may not always be 100% accurate, or could be lacking details and sufficient explanations.

Be Selective

This section is meant as a guide only. Do NOT copy/paste the entire collection of settings into your CAS configuration; rather pick only the properties that you need. Do NOT enable settings unless you are certain of their purpose and do NOT copy settings into your configuration only to keep them as reference. All these ideas lead to upgrade headaches, maintenance nightmares and premature aging.

YAGNI

Note that for nearly ALL use cases, declaring and configuring properties listed here is sufficient. You should NOT have to explicitly massage a CAS XML/Java/etc configuration file to design an authentication handler, create attribute release policies, etc. CAS at runtime will auto-configure all required changes for you. If you are unsure about the meaning of a given CAS setting, do NOT turn it on without hesitation. Review the codebase or better yet, ask questions to clarify the intended behavior.

Naming Convention

Property names can be specified in very relaxed terms. For instance cas.someProperty, cas.some-property, cas.some_property are all valid names. While all forms are accepted by CAS, there are certain components (in CAS and other frameworks used) whose activation at runtime is conditional on a property value, where this property is required to have been specified in CAS configuration using kebab case. This is both true for properties that are owned by CAS as well as those that might be presented to the system via an external library or framework such as Spring Boot, etc.

:information_source: Note

When possible, properties should be stored in lower-case kebab format, such as cas.property-name=value. The only possible exception to this rule is when naming actuator endpoints; The name of the actuator endpoints (i.e. ssoSessions) MUST remain in camelCase mode.

Settings and properties that are controlled by the CAS platform directly always begin with the prefix cas. All other settings are controlled and provided to CAS via other underlying frameworks and may have their own schemas and syntax. BE CAREFUL with the distinction. Unrecognized properties are rejected by CAS and/or frameworks upon which CAS depends. This means if you somehow misspell a property definition or fail to adhere to the dot-notation syntax and such, your setting is entirely refused by CAS and likely the feature it controls will never be activated in the way you intend.

Validation

Configuration properties are automatically validated on CAS startup to report issues with configuration binding, especially if defined CAS settings cannot be recognized or validated by the configuration schema. Additional validation processes are also handled via Configuration Metadata and property migrations applied automatically on startup by Spring Boot and family.

Indexed Settings

CAS settings able to accept multiple values are typically documented with an index, such as cas.some.setting[0]=value. The index [0] is meant to be incremented by the adopter to allow for distinct multiple configuration blocks.

Signed Assertions

CAS is able to ascertain the validity of assertion signatures using dedicated certificate files that are defined via CAS settings. Certificate files and resources may be defined statically as file-system resources that are available to CAS to load and use, or the signing resource may point to ADFS federation metadata (either as a URL or XML file). When using the federation metadata, the signing certificate is extracted from the IDPSSODescriptor key descriptor that is marked for signing.

Encrypted Assertions

CAS is able to automatically decrypt SAML assertions that are issued by ADFS. To do this, you will first need to generate a private/public keypair:

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openssl genrsa -out private.key 1024
openssl rsa -pubout -in private.key -out public.key -inform PEM -outform DER
openssl pkcs8 -topk8 -inform PEM -outform DER -nocrypt -in private.key -out private.p8
openssl req -new -x509 -key private.key -out x509.pem -days 365

# convert the X509 certificate to DER format
openssl x509 -outform der -in x509.pem -out certificate.crt

Configure CAS to reference the keypair, and configure the relying party trust settings in ADFS to use the certificate.crt file for encryption.

Modifying ADFS Claims

The WsFed configuration optionally may allow you to manipulate claims coming from ADFS but before they are inserted into the CAS user principal. The manipulation of the attributes is carried out using an attribute mutator where its logic may be implemented inside a Groovy script and whose path is taught to CAS via settings.

The script may take on the following form:

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import org.apereo.cas.*
import java.util.*
import org.apereo.cas.authentication.*

Map run(final Object... args) {
    def (attributes,logger) = args
    logger.warn("Mutating attributes {}", attributes)
    return [upn: ["CASUser"]]
}

The parameters passed to the script are as follows:

Parameter Description
attributes A current Map of attributes provided from ADFS.
logger The object responsible for issuing log messages such as logger.info(...).

Note that the execution result of the script MUST ensure that attributes are collected into a Map where the attribute name, the key, is a simple String and the attribute value is transformed into a collection.

To prepare CAS to support and integrate with Apache Groovy, please review this guide.

Handling CAS Logout

An optional step, the casLogoutView.html can be modified to place a link to ADFS’s logout page.

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<a href="https://adfs.example.org/adfs/ls/?wa=wsignout1.0">Logout</a>

Alternatively, you may instruct CAS to redirect to the above endpoint after logout operations have executed.

The following settings and properties are available from the CAS configuration catalog:

cas.logout.confirm-logoutBefore logout, allow the option to confirm on the web interface.
false

Before logout, allow the option to confirm on the web interface.

Type
Boolean
Default
false
Defined by
LogoutProperties
cas.logout.follow-service-redirectsWhether CAS should be allowed to redirect to an alternative location after logout.
false

Whether CAS should be allowed to redirect to an alternative location after logout.

Type
Boolean
Default
false
Defined by
LogoutProperties
cas.logout.redirect-parameterThe target destination to which CAS should redirect after logout is indicated and extracted by a parameter name of your choosing here.
no default

The target destination to which CAS should redirect after logout is indicated and extracted by a parameter name of your choosing here. If none specified, the default will be used as service.

Type
List<String>
Default
none
Defined by
LogoutProperties
cas.logout.redirect-urlA url to which CAS must immediately redirect after all logout operations have completed.
no default

A url to which CAS must immediately redirect after all logout operations have completed. Typically useful in scenarios where CAS is acting as a proxy and needs to redirect to an external identity provider's logout endpoint in order to remove a session, etc.

Type
String
Default
none
Defined by
LogoutProperties

Required settings may be needed to activate or affect the feature; review them even when they have a default. Optional settings only need to be set to change a default or to turn on the behavior they control. Third party settings belong to libraries such as Spring Boot that CAS builds on; their own documentation may have more detail.

Notes on configuration

Configuration Metadata

The collection of configuration properties listed in this section are automatically generated from the CAS source and components that contain the actual field definitions, types, descriptions, modules, etc. This metadata may not always be 100% accurate, or could be lacking details and sufficient explanations.

Be Selective

This section is meant as a guide only. Do NOT copy/paste the entire collection of settings into your CAS configuration; rather pick only the properties that you need. Do NOT enable settings unless you are certain of their purpose and do NOT copy settings into your configuration only to keep them as reference. All these ideas lead to upgrade headaches, maintenance nightmares and premature aging.

YAGNI

Note that for nearly ALL use cases, declaring and configuring properties listed here is sufficient. You should NOT have to explicitly massage a CAS XML/Java/etc configuration file to design an authentication handler, create attribute release policies, etc. CAS at runtime will auto-configure all required changes for you. If you are unsure about the meaning of a given CAS setting, do NOT turn it on without hesitation. Review the codebase or better yet, ask questions to clarify the intended behavior.

Naming Convention

Property names can be specified in very relaxed terms. For instance cas.someProperty, cas.some-property, cas.some_property are all valid names. While all forms are accepted by CAS, there are certain components (in CAS and other frameworks used) whose activation at runtime is conditional on a property value, where this property is required to have been specified in CAS configuration using kebab case. This is both true for properties that are owned by CAS as well as those that might be presented to the system via an external library or framework such as Spring Boot, etc.

:information_source: Note

When possible, properties should be stored in lower-case kebab format, such as cas.property-name=value. The only possible exception to this rule is when naming actuator endpoints; The name of the actuator endpoints (i.e. ssoSessions) MUST remain in camelCase mode.

Settings and properties that are controlled by the CAS platform directly always begin with the prefix cas. All other settings are controlled and provided to CAS via other underlying frameworks and may have their own schemas and syntax. BE CAREFUL with the distinction. Unrecognized properties are rejected by CAS and/or frameworks upon which CAS depends. This means if you somehow misspell a property definition or fail to adhere to the dot-notation syntax and such, your setting is entirely refused by CAS and likely the feature it controls will never be activated in the way you intend.

Validation

Configuration properties are automatically validated on CAS startup to report issues with configuration binding, especially if defined CAS settings cannot be recognized or validated by the configuration schema. Additional validation processes are also handled via Configuration Metadata and property migrations applied automatically on startup by Spring Boot and family.

Indexed Settings

CAS settings able to accept multiple values are typically documented with an index, such as cas.some.setting[0]=value. The index [0] is meant to be incremented by the adopter to allow for distinct multiple configuration blocks.

Per-Service Relying Party Id

In order to specify a relying party identifier per service definition, adjust your service registry to match the following:

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{
  "@class" : "org.apereo.cas.services.CasRegisteredService",
  "serviceId" : "^https://.+",
  "name" : "sample service",
  "id" : 100,
  "properties" : {
    "@class" : "java.util.HashMap",
    "wsfed.relyingPartyIdentifier" : {
      "@class" : "org.apereo.cas.services.DefaultRegisteredServiceProperty",
      "values" : [ "java.util.HashSet", [ "custom-identifier" ] ]
    }
  }
}

The following properties are available and recognized by CAS for various modules and features:

Name Default Value Type Group
wsfed.relyingPartyIdentifier STRING DELEGATED_AUTHN_WSFED

Troubleshooting

Be aware of clock drift issues between CAS and the ADFS server. Validation failures of the response do show up in the logs, and the request is routed back to ADFS again, causing redirect loops.

To enable additional logging, configure the log4j configuration file to add the following levels:

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...
<Logger name="org.apereo.cas.support.wsfederation" level="debug" additivity="false">
    <AppenderRef ref="casConsole"/>
    <AppenderRef ref="casFile"/>
</Logger>
...