WORKERS AHEAD!

You are viewing the development documentation for the Apereo CAS server. The functionality presented here is not officially released yet. This is a work in progress and will be continually updated as development moves forward. You are most encouraged to test the changes presented.

FIDO2 WebAuthn Multifactor Authentication - Attestation Trust & Metadata

WebAuthn support in CAS can handle authenticator attestation, which provides a way for the web service to request cryptographic proof of what authenticator the user is using.

Attestation trust metadata can be taught to CAS using the following strategies.

JSON
FIDO

WebAuthn attestation trust metadata can be loaded from a JSON file and CAS by default ships with and has enabled metadata offered by Yubico, for a series of devices that are also primarily offered by Yubico.

The structure of this JSON file is as follows:

{
  "identifier": "...",
  "version": 1,
  "vendorInfo": {
    "url": "...",
    "imageUrl": "...",
    "name": "..."
  },
  "trustedCertificates": [ "..." ],
  "devices": [
    {
      "deviceId": "...",
      "displayName": "...",
      "transports": 4,
      "deviceUrl": "...",
      "imageUrl": ".",
      "selectors": [
        {
          "type": "x509Extension",
          "parameters": {
            "key": "...",
            "value": {
              "type": "hex",
              "value": "..."
            }
          }
        }
      ]
    }
  ]
}

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.authn.mfa.web-authn.core.trust-source.trusted-device-metadata.location=

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, specially if the script 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.

org.apereo.cas.configuration.model.SpringResourceProperties.

_{How can I configure this property?}

Configuration properties can be included and activated using the following strategies.

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.

CAS properties can be specified using the Java configuration property syntax in any and all .properties files:

cas.authn.mfa.web-authn.core.trust-source.trusted-device-metadata.location=...

This is the most common form of property configuration that is recognized by CAS, regardless of the actual property source, which might in fact be managed separately outside the CAS environment, by another system or cloud framework.

CAS properties can be specified using the YAML syntax:

cas: 
  authn: 
    mfa: 
      web-authn: 
        core: 
          trust-source: 
            trusted-device-metadata: 
              location: "..."

Note that YAML is very specific about structure and indentation. Be sure to verify the correctness of the final result with your YAML validator of choice.

CAS properties can be passed to the CAS web application as system properties, when the application is launched:

java -Dcas.authn.mfa.web-authn.core.trust-source.trusted-device-metadata.location="..." -jar build/libs/cas.war

The above example assumes that the CAS web application is packaged as cas.war with an embedded server container and can be found in the build/libs directory. Note the placement of the system property which must be specified before the CAS web application is launched.

CAS properties can specified as system environment variables before the CAS web application is launched:

export CAS_AUTHN_MFA_WEB_AUTHN_CORE_TRUST_SOURCE_TRUSTED_DEVICE_METADATA_LOCATION="..."

java -jar build/libs/cas.war

The above example assumes that the CAS web application is packaged as cas.war with an embedded server container and can be found in the build/libs directory.

CAS properties can be passed to the CAS web application as command-line arguments, when the application is launched:

java -jar build/libs/cas.war --cas.authn.mfa.web-authn.core.trust-source.trusted-device-metadata.location="..."

The above example assumes that the CAS web application is packaged as cas.war with an embedded server container and can be found in the build/libs directory.

_{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.}

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.

Note

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 FIDO Alliance Metadata Service (MDS) is a centralized repository of the Metadata Statement that is used by the relying parties to validate authenticator attestation and prove the genuineness of the device model. MDS also provides information about certification status of the authenticators, and found security issues. Organizations deploying FIDO Authentication are able to use this information to select specific certification levels as required for compliance, and work through the security notifications to ensure effective incident response.

Usage

To activate this functionality, you will need to accept the legal terms and conditions that are put together by FIDO Alliance via CAS configuration by specifying the appropriate legal header.

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

cas.authn.mfa.web-authn.core.trust-source.fido.legal-header=

Set legal headers expected in the metadata BLOB. By using the FIDO Metadata Service, you will be subject to its terms of service. This setting serves two purposes:

To remind you and any adopters/reviewers that you need to read those terms of service before using this feature. To help you detect if the legal header changes, so you can take appropriate action.

If the legal header in the downloaded BLOB does not equal any of the expected headers, an exception will be thrown in the finalizing configuration step.

Note that CAS makes no guarantee that a change to the FIDO Metadata Service terms of service will also cause a change to the legal header in the BLOB.

The current legal header is noted by: #DEFAULT_LEGAL_HEADER which is the following:

"Retrieval and use of this BLOB indicates acceptance of the appropriate agreement located at https://fidoalliance.org/metadata/metadata-legal-terms/"

org.apereo.cas.configuration.model.support.mfa.webauthn.WebAuthnMultifactorAttestationTrustSourceFidoProperties.

_{How can I configure this property?}

Configuration properties can be included and activated using the following strategies.

Note

CAS properties can be specified using the Java configuration property syntax in any and all .properties files:

cas.authn.mfa.web-authn.core.trust-source.fido.legal-header=...

CAS properties can be specified using the YAML syntax:

cas: 
  authn: 
    mfa: 
      web-authn: 
        core: 
          trust-source: 
            fido: 
              legal-header: "..."

Note that YAML is very specific about structure and indentation. Be sure to verify the correctness of the final result with your YAML validator of choice.

CAS properties can be passed to the CAS web application as system properties, when the application is launched:

java -Dcas.authn.mfa.web-authn.core.trust-source.fido.legal-header="..." -jar build/libs/cas.war

CAS properties can specified as system environment variables before the CAS web application is launched:

export CAS_AUTHN_MFA_WEB_AUTHN_CORE_TRUST_SOURCE_FIDO_LEGAL_HEADER="..."

java -jar build/libs/cas.war

The above example assumes that the CAS web application is packaged as cas.war with an embedded server container and can be found in the build/libs directory.

CAS properties can be passed to the CAS web application as command-line arguments, when the application is launched:

java -jar build/libs/cas.war --cas.authn.mfa.web-authn.core.trust-source.fido.legal-header="..."

The above example assumes that the CAS web application is packaged as cas.war with an embedded server container and can be found in the build/libs directory.

cas.authn.mfa.web-authn.core.trust-source.fido.metadata-blob-url=https://mds.fidoalliance.org/

Download the metadata BLOB from the FIDO website. This is the current FIDO Metadata Service BLOB download URL.

org.apereo.cas.configuration.model.support.mfa.webauthn.WebAuthnMultifactorAttestationTrustSourceFidoProperties.

_{How can I configure this property?}

Configuration properties can be included and activated using the following strategies.

Note

CAS properties can be specified using the Java configuration property syntax in any and all .properties files:

cas.authn.mfa.web-authn.core.trust-source.fido.metadata-blob-url=https://mds.fidoalliance.org/

CAS properties can be specified using the YAML syntax:

cas: 
  authn: 
    mfa: 
      web-authn: 
        core: 
          trust-source: 
            fido: 
              metadata-blob-url: "https://mds.fidoalliance.org/"

Note that YAML is very specific about structure and indentation. Be sure to verify the correctness of the final result with your YAML validator of choice.

CAS properties can be passed to the CAS web application as system properties, when the application is launched:

java -Dcas.authn.mfa.web-authn.core.trust-source.fido.metadata-blob-url="https://mds.fidoalliance.org/" -jar build/libs/cas.war

CAS properties can specified as system environment variables before the CAS web application is launched:

export CAS_AUTHN_MFA_WEB_AUTHN_CORE_TRUST_SOURCE_FIDO_METADATA_BLOB_URL="https://mds.fidoalliance.org/"

java -jar build/libs/cas.war

The above example assumes that the CAS web application is packaged as cas.war with an embedded server container and can be found in the build/libs directory.

CAS properties can be passed to the CAS web application as command-line arguments, when the application is launched:

java -jar build/libs/cas.war --cas.authn.mfa.web-authn.core.trust-source.fido.metadata-blob-url="https://mds.fidoalliance.org/"

The above example assumes that the CAS web application is packaged as cas.war with an embedded server container and can be found in the build/libs directory.

cas.authn.mfa.web-authn.core.trust-source.fido.trust-root-hash=cbb522d7b7f127ad6a0113865bdf1cd4102e7d0759af635a7cf4720dc963c53b

Certificate SHA-256 hash required for PKI to verify the downloaded certificate. Separate hash values with a comma.

org.apereo.cas.configuration.model.support.mfa.webauthn.WebAuthnMultifactorAttestationTrustSourceFidoProperties.

_{How can I configure this property?}

Configuration properties can be included and activated using the following strategies.

Note

CAS properties can be specified using the Java configuration property syntax in any and all .properties files:

cas.authn.mfa.web-authn.core.trust-source.fido.trust-root-hash=cbb522d7b7f127ad6a0113865bdf1cd4102e7d0759af635a7cf4720dc963c53b

CAS properties can be specified using the YAML syntax:

cas: 
  authn: 
    mfa: 
      web-authn: 
        core: 
          trust-source: 
            fido: 
              trust-root-hash: "cbb522d7b7f127ad6a0113865bdf1cd4102e7d0759af635a7cf4720dc963c53b"

Note that YAML is very specific about structure and indentation. Be sure to verify the correctness of the final result with your YAML validator of choice.

CAS properties can be passed to the CAS web application as system properties, when the application is launched:

java -Dcas.authn.mfa.web-authn.core.trust-source.fido.trust-root-hash="cbb522d7b7f127ad6a0113865bdf1cd4102e7d0759af635a7cf4720dc963c53b" -jar build/libs/cas.war

CAS properties can specified as system environment variables before the CAS web application is launched:

export CAS_AUTHN_MFA_WEB_AUTHN_CORE_TRUST_SOURCE_FIDO_TRUST_ROOT_HASH="cbb522d7b7f127ad6a0113865bdf1cd4102e7d0759af635a7cf4720dc963c53b"

java -jar build/libs/cas.war

The above example assumes that the CAS web application is packaged as cas.war with an embedded server container and can be found in the build/libs directory.

CAS properties can be passed to the CAS web application as command-line arguments, when the application is launched:

java -jar build/libs/cas.war --cas.authn.mfa.web-authn.core.trust-source.fido.trust-root-hash="cbb522d7b7f127ad6a0113865bdf1cd4102e7d0759af635a7cf4720dc963c53b"

The above example assumes that the CAS web application is packaged as cas.war with an embedded server container and can be found in the build/libs directory.

cas.authn.mfa.web-authn.core.trust-source.fido.trust-root-url=https://secure.globalsign.com/cacert/root-r3.crt

Certificate required for PKI to verify the downloaded blob. This is the current FIDO Metadata Service trust root certificate. If the cert is downloaded, it is also written to the cache File. The certificate will be downloaded if it does not exist in the cache, or if the cached certificate is not currently valid.

org.apereo.cas.configuration.model.support.mfa.webauthn.WebAuthnMultifactorAttestationTrustSourceFidoProperties.

_{How can I configure this property?}

Configuration properties can be included and activated using the following strategies.

Note

CAS properties can be specified using the Java configuration property syntax in any and all .properties files:

cas.authn.mfa.web-authn.core.trust-source.fido.trust-root-url=https://secure.globalsign.com/cacert/root-r3.crt

CAS properties can be specified using the YAML syntax:

cas: 
  authn: 
    mfa: 
      web-authn: 
        core: 
          trust-source: 
            fido: 
              trust-root-url: "https://secure.globalsign.com/cacert/root-r3.crt"

Note that YAML is very specific about structure and indentation. Be sure to verify the correctness of the final result with your YAML validator of choice.

CAS properties can be passed to the CAS web application as system properties, when the application is launched:

java -Dcas.authn.mfa.web-authn.core.trust-source.fido.trust-root-url="https://secure.globalsign.com/cacert/root-r3.crt" -jar build/libs/cas.war

CAS properties can specified as system environment variables before the CAS web application is launched:

export CAS_AUTHN_MFA_WEB_AUTHN_CORE_TRUST_SOURCE_FIDO_TRUST_ROOT_URL="https://secure.globalsign.com/cacert/root-r3.crt"

java -jar build/libs/cas.war

The above example assumes that the CAS web application is packaged as cas.war with an embedded server container and can be found in the build/libs directory.

CAS properties can be passed to the CAS web application as command-line arguments, when the application is launched:

java -jar build/libs/cas.war --cas.authn.mfa.web-authn.core.trust-source.fido.trust-root-url="https://secure.globalsign.com/cacert/root-r3.crt"

The above example assumes that the CAS web application is packaged as cas.war with an embedded server container and can be found in the build/libs directory.

cas.authn.mfa.web-authn.core.trust-source.fido.blob-cache-file=

Cache metadata BLOB in the file cache file. If cache file exists, is a normal file, is readable, and is not out of date, then it will be used as the FIDO Metadata Service BLOB.

Otherwise, the metadata BLOB will be downloaded and written to this file.

org.apereo.cas.configuration.model.support.mfa.webauthn.WebAuthnMultifactorAttestationTrustSourceFidoProperties.

_{How can I configure this property?}

Configuration properties can be included and activated using the following strategies.

Note

CAS properties can be specified using the Java configuration property syntax in any and all .properties files:

cas.authn.mfa.web-authn.core.trust-source.fido.blob-cache-file=...

CAS properties can be specified using the YAML syntax:

cas: 
  authn: 
    mfa: 
      web-authn: 
        core: 
          trust-source: 
            fido: 
              blob-cache-file: "..."

Note that YAML is very specific about structure and indentation. Be sure to verify the correctness of the final result with your YAML validator of choice.

CAS properties can be passed to the CAS web application as system properties, when the application is launched:

java -Dcas.authn.mfa.web-authn.core.trust-source.fido.blob-cache-file="..." -jar build/libs/cas.war

CAS properties can specified as system environment variables before the CAS web application is launched:

export CAS_AUTHN_MFA_WEB_AUTHN_CORE_TRUST_SOURCE_FIDO_BLOB_CACHE_FILE="..."

java -jar build/libs/cas.war

The above example assumes that the CAS web application is packaged as cas.war with an embedded server container and can be found in the build/libs directory.

CAS properties can be passed to the CAS web application as command-line arguments, when the application is launched:

java -jar build/libs/cas.war --cas.authn.mfa.web-authn.core.trust-source.fido.blob-cache-file="..."

The above example assumes that the CAS web application is packaged as cas.war with an embedded server container and can be found in the build/libs directory.

cas.authn.mfa.web-authn.core.trust-source.fido.trust-root-cache-file=

Cache the trust root certificate in the file cache file. If cache file exists, is a normal file, is readable, matches one of the SHA-256 hashes configured in and contains a currently valid X.509 certificate, then it will be used as the trust root for the FIDO Metadata Service blob.

Otherwise, the trust root certificate will be downloaded and written to this file.

org.apereo.cas.configuration.model.support.mfa.webauthn.WebAuthnMultifactorAttestationTrustSourceFidoProperties.

_{How can I configure this property?}

Configuration properties can be included and activated using the following strategies.

Note

CAS properties can be specified using the Java configuration property syntax in any and all .properties files:

cas.authn.mfa.web-authn.core.trust-source.fido.trust-root-cache-file=...

CAS properties can be specified using the YAML syntax:

cas: 
  authn: 
    mfa: 
      web-authn: 
        core: 
          trust-source: 
            fido: 
              trust-root-cache-file: "..."

Note that YAML is very specific about structure and indentation. Be sure to verify the correctness of the final result with your YAML validator of choice.

CAS properties can be passed to the CAS web application as system properties, when the application is launched:

java -Dcas.authn.mfa.web-authn.core.trust-source.fido.trust-root-cache-file="..." -jar build/libs/cas.war

CAS properties can specified as system environment variables before the CAS web application is launched:

export CAS_AUTHN_MFA_WEB_AUTHN_CORE_TRUST_SOURCE_FIDO_TRUST_ROOT_CACHE_FILE="..."

java -jar build/libs/cas.war

The above example assumes that the CAS web application is packaged as cas.war with an embedded server container and can be found in the build/libs directory.

CAS properties can be passed to the CAS web application as command-line arguments, when the application is launched:

java -jar build/libs/cas.war --cas.authn.mfa.web-authn.core.trust-source.fido.trust-root-cache-file="..."

The above example assumes that the CAS web application is packaged as cas.war with an embedded server container and can be found in the build/libs directory.

Configuration Metadata

Be Selective

YAGNI

Naming Convention

Note