SSO Cookie

A ticket-granting cookie is an HTTP cookie set by CAS upon the establishment of a single sign-on session. This cookie maintains login state for the client, and while it is valid, the client can present it to CAS in lieu of primary credentials.

The cookie value is linked to the active ticket-granting ticket, the remote IP address that initiated the request as well as the user agent that submitted the request. The final cookie value is then encrypted and signed.

These keys MUST be regenerated per your specific environment. Each key is a JSON Web Token with a defined length per the algorithm used for encryption and signing.

In the event that keys are not generated by the deployer, CAS will attempt to auto-generate keys and will output the result for each respected key. The deployer MUST attempt to copy the generated keys over to the appropriate settings in their CAS properties file, specially when running a multi-node CAS deployment. Failure to do so will prevent CAS to appropriate decrypt and encrypt the cookie value and will prevent successful single sign-on.

:information_source: Forced Authentication

Each application can opt out of a single sign-on session on a per-request basis. The availability of this behavior does depend on the authentication protocol used by the application. For example, applications that use the CAS protocol can opt out of single sign-on through the renew parameter or the CAS server may conditionally opt the service out based on the policies defined for the application in the service registry

Configuration

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

The configuration settings listed below are tagged as Required in the CAS configuration metadata. This flag indicates that the presence of the setting may be needed to activate or affect the behavior of the CAS feature and generally should be reviewed, possibly owned and adjusted. If the setting is assigned a default value, you do not need to strictly put the setting in your copy of the configuration, but should review it nonetheless to make sure it matches your deployment expectations.

  • cas.tgc.crypto.encryption.key=
  • The encryption key is a JWT whose length is defined by the encryption key size setting.

    This setting supports the Spring Expression Language.

    org.apereo.cas.configuration.model.core.util.EncryptionJwtCryptoProperties.

    How can I configure this property?

  • cas.tgc.crypto.signing.key=
  • The signing key is a JWT whose length is defined by the signing key size setting.

    This setting supports the Spring Expression Language.

    org.apereo.cas.configuration.model.core.util.SigningJwtCryptoProperties.

    How can I configure this property?

    The configuration settings listed below are tagged as Optional in the CAS configuration metadata. This flag indicates that the presence of the setting is not immediately necessary in the end-user CAS configuration, because a default value is assigned or the activation of the feature is not conditionally controlled by the setting value. In other words, you should only include this field in your configuration if you need to modify the default value or if you need to turn on the feature controlled by the setting.

  • cas.tgc.allowed-ip-addresses-pattern=
  • 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.

    This settings supports regular expression patterns. [?].

    org.apereo.cas.configuration.model.support.cookie.TicketGrantingCookieProperties.

    How can I configure this property?

  • cas.tgc.auto-configure-cookie-path=true
  • Decide if cookie paths should be automatically configured based on the application context path, when the cookie path is not configured.

    org.apereo.cas.configuration.model.support.cookie.TicketGrantingCookieProperties.

    How can I configure this property?

  • cas.tgc.domain=
  • 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.

    org.apereo.cas.configuration.model.support.cookie.TicketGrantingCookieProperties.

    How can I configure this property?

  • cas.tgc.geo-locate-client-session=false
  • 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.

    org.apereo.cas.configuration.model.support.cookie.TicketGrantingCookieProperties.

    How can I configure this property?

  • cas.tgc.http-only=true
  • true if this cookie contains the HttpOnly attribute. This means that the cookie should not be accessible to scripting engines, like javascript.

    org.apereo.cas.configuration.model.support.cookie.TicketGrantingCookieProperties.

    How can I configure this property?

  • cas.tgc.max-age=-1
  • 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.

    org.apereo.cas.configuration.model.support.cookie.TicketGrantingCookieProperties.

    How can I configure this property?

  • cas.tgc.name=
  • 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.

    org.apereo.cas.configuration.model.support.cookie.TicketGrantingCookieProperties.

    How can I configure this property?

  • cas.tgc.path=
  • 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.

    org.apereo.cas.configuration.model.support.cookie.TicketGrantingCookieProperties.

    How can I configure this property?

  • cas.tgc.pin-to-session=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.

    org.apereo.cas.configuration.model.support.cookie.TicketGrantingCookieProperties.

    How can I configure this property?

  • cas.tgc.remember-me-max-age=P14D
  • If remember-me is enabled, specifies the maximum age of the cookie.

    This settings supports the java.time.Duration syntax [?].

    org.apereo.cas.configuration.model.support.cookie.TicketGrantingCookieProperties.

    How can I configure this property?

  • cas.tgc.same-site-policy=
  • 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

    org.apereo.cas.configuration.model.support.cookie.TicketGrantingCookieProperties.

    How can I configure this property?

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

    org.apereo.cas.configuration.model.support.cookie.TicketGrantingCookieProperties.

    How can I configure this property?

  • cas.tgc.crypto.alg=
  • The signing/encryption algorithm to use.

    org.apereo.cas.configuration.model.core.util.EncryptionJwtSigningJwtCryptographyProperties.

    How can I configure this property?

  • cas.tgc.crypto.enabled=true
  • Whether crypto operations are enabled.

    org.apereo.cas.configuration.model.core.util.EncryptionJwtSigningJwtCryptographyProperties.

    How can I configure this property?

  • cas.tgc.crypto.encryption.key-size=512
  • The encryption key size.

    org.apereo.cas.configuration.model.core.util.EncryptionJwtCryptoProperties.

    How can I configure this property?

  • cas.tgc.crypto.signing.key-size=512
  • The signing key size.

    org.apereo.cas.configuration.model.core.util.SigningJwtCryptoProperties.

    How can I configure this property?

  • cas.tgc.crypto.strategy-type=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.

    org.apereo.cas.configuration.model.core.util.EncryptionJwtSigningJwtCryptographyProperties.

    How can I configure this property?

  • cas.tgc.crypto.encryption.key=
  • The encryption key is a JWT whose length is defined by the encryption key size setting.

    This setting supports the Spring Expression Language.

    org.apereo.cas.configuration.model.core.util.EncryptionJwtCryptoProperties.

    How can I configure this property?

  • cas.tgc.crypto.signing.key=
  • The signing key is a JWT whose length is defined by the signing key size setting.

    This setting supports the Spring Expression Language.

    org.apereo.cas.configuration.model.core.util.SigningJwtCryptoProperties.

    How can I configure this property?

  • cas.tgc.crypto.alg=
  • The signing/encryption algorithm to use.

    org.apereo.cas.configuration.model.core.util.EncryptionJwtSigningJwtCryptographyProperties.

    How can I configure this property?

  • cas.tgc.crypto.enabled=true
  • Whether crypto operations are enabled.

    org.apereo.cas.configuration.model.core.util.EncryptionJwtSigningJwtCryptographyProperties.

    How can I configure this property?

  • cas.tgc.crypto.encryption.key-size=512
  • The encryption key size.

    org.apereo.cas.configuration.model.core.util.EncryptionJwtCryptoProperties.

    How can I configure this property?

  • cas.tgc.crypto.signing.key-size=512
  • The signing key size.

    org.apereo.cas.configuration.model.core.util.SigningJwtCryptoProperties.

    How can I configure this property?

  • cas.tgc.crypto.strategy-type=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.

    org.apereo.cas.configuration.model.core.util.EncryptionJwtSigningJwtCryptographyProperties.

    How can I configure this property?

    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:

    1
    2
    
    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:

    1
    2
    3
    4
    5
    
    {
      "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.


    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, specially 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.

    The cookie has the following properties:

    1. It is marked as secure.
    2. Depending on container support, the cookie would be marked as http-only automatically.
    3. The cookie value is encrypted and signed via secret keys that need to be generated upon deployment.

    If keys are left undefined, on startup CAS will notice that no keys are defined and it will appropriately generate keys for you automatically. Your CAS logs will then show the following snippet:

    1
    2
    3
    4
    
    WARN [...] - <Secret key for encryption is not defined. CAS will auto-generate the encryption key>
    WARN [...] - <Generated encryption key ABC of size ... . The generated key MUST be added to CAS settings.>
    WARN [...] - <Secret key for signing is not defined. CAS will auto-generate the signing key>
    WARN [...] - <Generated signing key XYZ of size ... . The generated key MUST be added to CAS settings.>
    

    You should then grab each generated key for encryption and signing, and put them inside your CAS properties for each setting. If you wish you manually generate keys, you may use the following tool.

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

    The configuration settings listed below are tagged as Required in the CAS configuration metadata. This flag indicates that the presence of the setting may be needed to activate or affect the behavior of the CAS feature and generally should be reviewed, possibly owned and adjusted. If the setting is assigned a default value, you do not need to strictly put the setting in your copy of the configuration, but should review it nonetheless to make sure it matches your deployment expectations.

    The configuration settings listed below are tagged as Optional in the CAS configuration metadata. This flag indicates that the presence of the setting is not immediately necessary in the end-user CAS configuration, because a default value is assigned or the activation of the feature is not conditionally controlled by the setting value. In other words, you should only include this field in your configuration if you need to modify the default value or if you need to turn on the feature controlled by the setting.

  • cas.sso.create-sso-cookie-on-renew-authn=true
  • Flag that indicates whether to create SSO session on re-newed authentication event.

    org.apereo.cas.configuration.model.core.sso.SingleSignOnProperties.

    How can I configure this property?

  • cas.sso.proxy-authn-enabled=true
  • Indicates whether CAS proxy authentication/tickets are supported by this server implementation.

    org.apereo.cas.configuration.model.core.sso.SingleSignOnProperties.

    How can I configure this property?

  • cas.sso.renew-authn-enabled=true
  • Indicates whether this server implementation should globally support CAS protocol authentication requests that are tagged with "renew=true".

    org.apereo.cas.configuration.model.core.sso.SingleSignOnProperties.

    How can I configure this property?

  • cas.sso.services.allow-missing-service-parameter=true
  • Flag that indicates whether to allow SSO session with a missing target service.

    By default, CAS will present a generic success page if the initial authentication request does not identify the target application. In some cases, the ability to login to CAS without logging in to a particular service may be considered a misfeature because in practice, too few users and institutions are prepared to understand, brand, and support what is at best a fringe use case of logging in to CAS for the sake of establishing an SSO session without logging in to any CAS-reliant service.

    org.apereo.cas.configuration.model.core.sso.SingleSignOnServicesProperties.

    How can I configure this property?

  • cas.sso.services.required-service-pattern=
  • A regular expression pattern that represents an application which must have established a session with CAS already before access to other applications can be allowed by CAS. This is the initial mandatory/required application with which the user must start before going anywhere else. Services that establish a session with CAS typically do so by receiving a service ticket from CAS.

    This settings supports regular expression patterns. [?].

    org.apereo.cas.configuration.model.core.sso.SingleSignOnServicesProperties.

    How can I configure this property?

  • cas.sso.sso-enabled=true
  • Indicate whether single sign-on should be turned on and supported globally for the server.

    org.apereo.cas.configuration.model.core.sso.SingleSignOnProperties.

    How can I configure this property?

    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, specially 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.

    SSO Expiration Policy

    The single sign-on expiration policy that is tied to the CAS single sign-on cookie is mainly controlled by a specific ticket type that represents the single sign-on session managed by the CAS server.

    See this page for more.

    SameSite Attribute

    CAS configuration allows the deployer to control and modify the SameAttribute cookie attribute statically. The deployer also has the option to generate this cookie attribute dynamically via the following strategies.

    • The cookie setting in CAS configuration may point to a Groovy script that is tasked to generate the SameAttribute cookie attribute. The outline of the script may be as follows:

      1
      2
      3
      4
      5
      6
      7
      8
      
      import org.apereo.cas.web.cookie.*
      
      def run(final Object... args) {
          def (request,response,context,logger) = args
          
          logger.info("Generating SameSite for ${context.name}")
          return "SameSite=Lax;"
      }
      

      The parameters that may be passed are as follows:

      Parameter Description
      request The HTTP request object.
      response The HTTP response object.
      context The cookie configuration context that points to the cookie configuration and other helper objects.
      logger The object responsible for issuing log messages such as logger.info(...).
    • The cookie setting in CAS configuration may point to a Java class using its FQDN that is tasked to generate the SameAttribute cookie attribute.

      1
      2
      3
      4
      5
      6
      7
      8
      
      public class MyCookieSameSitePolicy implements CookieSameSitePolicy {
          @Override
          public Optional<String> build(HttpServletRequest request, 
                                        HttpServletResponse response, 
                                        CookieGenerationContext context) {
              return Optional.of("SameSite=Lax;");
          }
      }
      

    By default, forced authentication requests that challenge the user for credentials either via the renew request parameter (that is, using the CAS protocol), or via the service-specific setting of the CAS service registry will always generate the ticket-granting cookie nonetheless. What this means is, logging in to a non-SSO-participating application via CAS nonetheless creates a valid CAS single sign-on session that will be honored on a subsequent attempt to authenticate to a SSO-participating application.

    The cookie generation strategy can also be customized on a per-application basis. For additional details, please review this guide.