Ticket-Granting Ticket Policies

TGT expiration policy governs the time span during which an authenticated user may grant STs with a valid (non-expired) TGT without having to re-authenticate. An attempt to grant an ST with an expired TGT would require the user to re-authenticate to obtain a new (valid) TGT.

Ticket expiration policies are activated in the following conditions:

  • If the timeout values for the default policy are all set to zero or less, CAS shall ensure tickets are never considered expired.
  • Disabling a policy requires that all its timeout settings be set to a value equal or less than zero.
  • If not ticket expiration policy is determined, CAS shall ensure the ticket are always considered expired.
:information_source: Keep What You Need!

You are encouraged to only keep and maintain properties and settings needed for a particular policy. It is UNNECESSARY to grab a copy of all fields or keeping a copy as a reference while leaving them commented out. This strategy would ultimately lead to poor upgrades increasing chances of breaking changes and a messy deployment at that.

Ticket expiration policies are activated in the following order:

  1. Tickets are never expired, if and when settings for the default policy are configured accordingly.
  2. Timeout
  3. Default
  4. Throttled Timeout
  5. Hard Timeout
  6. Tickets always expire immediately.

  • This policy provides a hard-time out as well as a sliding window.

    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.ticket.tgt.core.max-length=50

    • Maximum length of tickets.

    org.apereo.cas.configuration.model.core.ticket.TicketGrantingTicketCoreProperties.

    How can I configure this property?

  • cas.ticket.tgt.core.only-track-most-recent-session=true

    • Flag to control whether to track most recent SSO sessions. As multiple tickets may be issued for the same application, this impacts how session information is tracked for every ticket which then has a subsequent impact on logout.

    org.apereo.cas.configuration.model.core.ticket.TicketGrantingTicketCoreProperties.

    How can I configure this property?

  • cas.ticket.tgt.primary.max-time-to-live-in-seconds=PT8H

    • Maximum time in seconds tickets would be live in CAS server.

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

    org.apereo.cas.configuration.model.core.ticket.PrimaryTicketExpirationPolicyProperties.

    How can I configure this property?

  • cas.ticket.tgt.primary.time-to-kill-in-seconds=PT2H

    • Time in seconds after which tickets would be destroyed after a period of inactivity.

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

    org.apereo.cas.configuration.model.core.ticket.PrimaryTicketExpirationPolicyProperties.

    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.

  • This ticket expiration policy is conditionally activated if and when the authenticated principal contains a authenticationSessionTimeout attribute. This attribute is expected to be a single-valued attribute whose value, measured in seconds, would allow CAS to build a hard timeout expiration policy and associate it with the ticket-granting ticket. The value may be specified a numeric value or in the Duration syntax, i.e. PT2H.

  • The expiration policy of ticket granting tickets can be conditionally decided on a per-application basis. The candidate service whose ticket granting ticket expiration policy is to deviate from the default configuration must be designed as such:

    

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    {
    "@class" : "org.apereo.cas.services.CasRegisteredService",
    "serviceId" : "^https://.*",
    "name" : "Sample",
    "id" : 10,
    "ticketGrantingTicketExpirationPolicy": {
      "@class": "org.apereo.cas.services.DefaultRegisteredServiceTicketGrantingTicketExpirationPolicy",
      "maxTimeToLiveInSeconds": 5
    }
}

    Remember that applications are responsible to manage their own session. CAS will not and cannot manage the application session and generally has no control over the application’s timeout policies, logout practices, etc. The expiration policy of the ticket-granting ticket per application allows to CAS to use that policy as an override and separate from the global defaults, at the time the ticket is constructed and only if the incoming service request matches that given registered service definition. Once created, the policy remains global and affects all other applications and it has nothing to do with how the application manages its own sessions.

  • The expiration policy applied to TGTs provides for most-recently-used expiration policy, similar to a Web server session timeout. For example, a 2-hour time span with this policy in effect would require a TGT to be used every 2 hours or less, otherwise it would be marked as expired.

    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.ticket.tgt.timeout.max-time-to-live-in-seconds=

    • Maximum time in seconds. for TGTs to be live in CAS server.

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

    org.apereo.cas.configuration.model.core.ticket.TimeoutTicketExpirationPolicyProperties.

    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.

  • The hard timeout policy provides for finite ticket lifetime as measured from the time of creation. For example, a 4-hour time span for this policy means that a ticket created at 1PM may be used up until 5PM; subsequent attempts to use it will mark it expired and the user will be forced to re-authenticate.

    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.ticket.tgt.hard-timeout.time-to-kill-in-seconds=

    • Timeout in seconds to kill the session and consider tickets expired.

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

    org.apereo.cas.configuration.model.core.ticket.HardTimeoutTicketExpirationPolicyProperties.

    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.

  • The throttled timeout policy extends the TimeoutExpirationPolicy with the concept of throttling where a ticket may be used at most every N seconds. This policy was designed to thwart denial of service conditions where a rogue or misconfigured client attempts to consume CAS server resources by requesting high volumes of service tickets in a short time.

    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.ticket.tgt.throttled-timeout.time-in-between-uses-in-seconds=

    • Timeout in between each attempt.

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

    org.apereo.cas.configuration.model.core.ticket.ThrottledTimeoutTicketExpirationPolicyProperties.

    How can I configure this property?

  • cas.ticket.tgt.throttled-timeout.time-to-kill-in-seconds=

    • Timeout in seconds to kill the session and consider tickets expired.

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

    org.apereo.cas.configuration.model.core.ticket.ThrottledTimeoutTicketExpirationPolicyProperties.

    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.

  • The never expires policy allows tickets to exist indefinitely. This policy is activated when the primary ticket expiration policy is configured with negative timeout values.

    :warning: Usage Warning!

    Use of this policy has significant consequences to overall security policy and should be enabled only after a thorough review by a qualified security team. There are also implications to server resource usage for the ticket registries backed by filesystem storage. Since disk storage for tickets can never be reclaimed for those registries with this policy in effect, use of this policy with those ticket registry implementations is strongly discouraged.

How Do I Choose?

Changing the TGT policy is a matter of organizational policy, and typically one that would control the length of the overall SSO session for the best user experience. Unless you have good reason to do so or a business use case dictates a scenario, the defaults generally are appropriate. Overall, you want to try to keep the length of the SSO session to a minimum to avoid security issues, but not too small to cause user annoyance with repeated logins.