Simple Multifactor Authentication

Allow CAS to act as a multifactor authentication provider on its own, issuing tokens and sending them to end-users via pre-defined communication channels such as email or text messages. Tokens issued by CAS are tracked using the ticket registry and are assigned a configurable expiration policy controlled via CAS settings.

Configuration

Support is enabled by including the following module in the overlay:

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

dependencies {  
  implementation "org.apereo.cas:cas-server-support-simple-mfa"
}

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 is not strictly necessary in the end-user CAS configuration, because a default value may be assigned or the feature in question may not be immediately intended for use. You may want to own the setting and update it assigned value, assuming the intended feature controlled by the setting is utilized.

  • cas.authn.mfa.simple.bypass.groovy.location=
  • The location of the resource. Resources can be URLS, or files found either on the classpath or outside somewhere in the file system.

  • cas.authn.mfa.simple.bypass.rest.url=
  • The endpoint URL to contact and retrieve attributes.

    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.

  • cas.authn.mfa.simple.failure-mode=UNDEFINED
  • The failure mode policy for this MFA provider. The following failure modes are supported:

    • CLOSED: Authentication is blocked if the provider cannot be reached.
    • OPEN: Authentication proceeds yet requested MFA is NOT communicated to the client if provider is unavailable.
    • PHANTOM: Authentication proceeds and requested MFA is communicated to the client if provider is unavailable.
    • NONE: Do not contact the provider at all to check for availability. Assume the provider is available.

  • cas.authn.mfa.simple.id=
  • The identifier for the multifactor provider. In most cases, this need not be configured explicitly, unless multiple instances of the same provider type are configured in CAS.

  • cas.authn.mfa.simple.name=
  • The name of the authentication handler used to verify credentials in MFA.

  • cas.authn.mfa.simple.order=
  • The order of the authentication handler in the chain.

  • cas.authn.mfa.simple.rank=0
  • At times, CAS needs to determine the correct provider when step-up authentication is required. Consider for a moment that CAS already has established an SSO session with/without a provider and has reached a level of authentication. Another incoming request attempts to exercise that SSO session with a different and often competing authentication requirement that may differ from the authentication level CAS has already established. Concretely, examples may be:

    • CAS has achieved an SSO session, but a separate request now requires step-up authentication with DuoSecurity.
    • CAS has achieved an SSO session with an authentication level satisfied by DuoSecurity, but a separate request now requires step-up authentication with YubiKey.
    In certain scenarios, CAS will attempt to rank authentication levels and compare them with each other. If CAS already has achieved a level that is higher than what the incoming request requires, no step-up authentication will be performed. If the opposite is true, CAS will route the authentication flow to the required authentication level and upon success, will adjust the SSO session with the new higher authentication level now satisfied. Ranking of authentication methods is done per provider via specific properties for each. Note that the higher the rank value is, the higher on the security scale it remains. A provider that ranks higher with a larger weight value trumps and override others with a lower value.

  • cas.authn.mfa.simple.time-to-kill-in-seconds=30
  • Time in seconds that CAS tokens should be considered live in CAS server.

  • cas.authn.mfa.simple.token-length=6
  • The length of the generated token.

  • cas.authn.mfa.simple.trusted-device-enabled=false
  • Indicates whether this provider should support trusted devices.

  • cas.authn.mfa.simple.bypass.authentication-attribute-name=
  • Skip multifactor authentication based on designated authentication attribute names.

  • cas.authn.mfa.simple.bypass.authentication-attribute-value=
  • Optionally, skip multifactor authentication based on designated authentication attribute values.

  • cas.authn.mfa.simple.bypass.authentication-handler-name=
  • Skip multifactor authentication depending on form of primary authentication execution. Specifically, skip multifactor if the a particular authentication handler noted by its name successfully is able to authenticate credentials in the primary factor.

  • cas.authn.mfa.simple.bypass.authentication-method-name=
  • Skip multifactor authentication depending on method/form of primary authentication execution. Specifically, skip multifactor if the authentication method attribute collected as part of authentication metadata matches a certain value.

  • cas.authn.mfa.simple.bypass.credential-class-type=
  • Skip multifactor authentication depending on form of primary credentials. Value must equal the fully qualified class name of the credential type.

  • cas.authn.mfa.simple.bypass.http-request-headers=
  • Skip multifactor authentication if the http request contains the defined header names. Header names may be comma-separated and can be regular expressions; values are ignored.

  • cas.authn.mfa.simple.bypass.http-request-remote-address=
  • Skip multifactor authentication if the http request's remote address or host matches the value defined here. The value may be specified as a regular expression.

  • cas.authn.mfa.simple.bypass.principal-attribute-name=
  • Skip multifactor authentication based on designated principal attribute names.

  • cas.authn.mfa.simple.bypass.principal-attribute-value=
  • Optionally, skip multifactor authentication based on designated principal attribute values.

  • cas.authn.mfa.simple.bypass.rest.basic-auth-password=
  • If REST endpoint is protected via basic authentication, specify the password for authentication.

  • cas.authn.mfa.simple.bypass.rest.basic-auth-username=
  • If REST endpoint is protected via basic authentication, specify the username for authentication.

  • cas.authn.mfa.simple.bypass.rest.method=GET
  • HTTP method to use when contacting the rest endpoint. Examples include GET, POST, etc.