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.
Configuration
Support is enabled by including the following module in the overlay:
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<dependency>
<groupId>org.apereo.cas</groupId>
<artifactId>cas-server-support-simple-mfa</artifactId>
<version>${cas.version}</version>
</dependency>
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implementation "org.apereo.cas:cas-server-support-simple-mfa:${project.'cas.version'}"
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dependencyManagement {
imports {
mavenBom "org.apereo.cas:cas-server-support-bom:${project.'cas.version'}"
}
}
dependencies {
implementation "org.apereo.cas:cas-server-support-simple-mfa"
}
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dependencies {
/*
The following platform references should be included automatically and are listed here for reference only.
implementation enforcedPlatform("org.apereo.cas:cas-server-support-bom:${project.'cas.version'}")
implementation platform(org.springframework.boot.gradle.plugin.SpringBootPlugin.BOM_COORDINATES)
*/
implementation "org.apereo.cas:cas-server-support-simple-mfa"
}
The following settings and properties are available from the CAS configuration catalog:
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. 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 ofinotify 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.
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cas.authn.mfa.simple.bypass.rest.url=
The endpoint URL to contact and retrieve attributes.
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cas.authn.mfa.simple.bypass.authentication-attribute-name=
Skip multifactor authentication based on designated authentication attribute names.
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cas.authn.mfa.simple.bypass.authentication-attribute-value=
Optionally, skip multifactor authentication based on designated authentication attribute values.
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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.
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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.
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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.
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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.
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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.
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cas.authn.mfa.simple.bypass.principal-attribute-name=
Skip multifactor authentication based on designated principal attribute names.
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cas.authn.mfa.simple.bypass.principal-attribute-value=
Optionally, skip multifactor authentication based on designated principal attribute values.
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cas.authn.mfa.simple.bypass.rest.basic-auth-password=
If REST endpoint is protected via basic authentication, specify the password for authentication.
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cas.authn.mfa.simple.bypass.rest.basic-auth-username=
If REST endpoint is protected via basic authentication, specify the username for authentication.
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cas.authn.mfa.simple.bypass.rest.headers=
Headers, defined as a Map, to include in the request when making the REST call. Will overwrite any header that CAS is pre-defined to send and include in the request. Key in the map should be the header name and the value in the map should be the header value.
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cas.authn.mfa.simple.bypass.rest.method=GET
HTTP method to use when contacting the rest endpoint. Examples include
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cas.authn.mfa.simple.failure-mode=CLOSED
The failure mode policy for this MFA provider. The authentication policy by default supports fail-closed mode, which means that if you attempt to exercise a particular provider available to CAS and the provider cannot be reached, authentication will be stopped and an error will be displayed. You can of course change this behavior so that authentication proceeds without exercising the provider functionality, if that provider cannot respond. Each defined multifactor authentication provider can set its own failure mode policy. Failure modes set at this location will override the global failure mode, but defer to any failure mode set by the registered service. Available values are as follows:
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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.
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cas.authn.mfa.simple.name=
The name of the authentication handler used to verify credentials in MFA. Remember that if you have more than one authentication handler of the same type, the names must be defined uniquely for each authentication scheme. Failing to do so may force CAS to not register authentication handlers with a duplicate name.
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cas.authn.mfa.simple.order=
The order of the authentication handler in the chain.
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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:
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cas.authn.mfa.simple.trusted-device-enabled=false
Indicates whether this provider should support trusted devices.
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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.
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. The validation process is on by default and can be skipped on startup using a special system
property SKIP_CONFIG_VALIDATION that should be set to true. 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.
Registration
Registration is expected to have occurred as an out-of-band process. Ultimately, CAS expects to fetch the necessary attributes from configured attribute sources to determine communications channels for email and/or sms. The adopter is expected to have populated user records with enough information to indicate a phone number and/or email address where CAS could then be configured to fetch and examine those attributes to share generated tokens.
Communication Strategy
Please see this guide.
Rate Limiting
Please see this guide.
Token Management
Please see this guide.