SAML2SSOConfiguration

Options common to most/all profiles:

Guidance

Modifying the security configuration is usually done to:

• specify an alternate signing or decryption key to use

• control signing or encryption algorithms (but for metadata you control, it's advisable to control algorithms by using an extension to specify supported algorithms).

The two interceptor lists allow the much less commonly used profile interceptor injection points to be used. This is largely a Java-based way of doing very low-level sorts of “message rewriting” hackery that might otherwise be impossible to pull off. One use case for the inbound side might be picking up non-standard parameters in a SAML request.

Options common to profiles that perform authentication:

Guidance

The postAuthenticationFlows property is used to apply special processing to requests, such as attribute release consent, password expiration warnings, authorization checks, or other custom processing.

Examples of postAuthenticationFlows property

<bean id="shibboleth.DefaultRelyingParty" parent="RelyingParty">

	<!-- Add consent to Shibboleth SSO profile. -->
	<bean parent="Shibboleth.SSO" p:postAuthenticationFlows="attribute-release" />

	<!-- Add consent, followed by expiring password check, to SAML 2 SSO profile. -->
	<bean parent="SAML2.SSO" p:postAuthenticationFlows="#{{'attribute-release', 'expiring-password'}}" />

	<!-- Return interceptors from a function bean (not shown). -->
	<bean parent="Shibboleth.SSO" p:postAuthenticationFlowsLookupStrategy-ref="InterceptorsFunction" />

</bean>

With the increased use of multi-factor authentication, it is more common to find RPs that can specify authentication requirements, but there are still many cases, particular with commercial services, in which it becomes necessary to force the use of specific login methods. This can be achieved using the defaultAuthenticationMethods property by specifying one or more corresponding Principals to trigger the use of stronger methods.

Note that you must also prevent a malicious actor from overriding this preference for a SAML 2.0 SP by manufacturing a request, via one of two means:

• For a SAML 2.0 SP that can sign its requests, its metadata can be modified with the AuthnRequestsSigned flag to indicate that its requests must be signed.

• Alternatively, the disallowedFeatures property may be set with the SAML2.SSO.FEATURE_AUTHNCONTEXT bean to block use of the SAML 2.0 <RequestedAuthnContext> feature.

At present, no other authentication profiles support a feature capable of requesting the authentication method.

Examples of defaultAuthenticationMethods property

<!-- NOTE: these example.org constants are examples and are not suitable for real use. -->
<bean id="MFASAML2Principal" parent="shibboleth.SAML2AuthnContextClassRef"
	c:_0="http://example.org/ac/classes/mfa" />
<bean id="MFASAML1Principal" parent="shibboleth.SAML1AuthenticationMethod"
	c:_0="http://example.org/ac/classes/mfa" />

<bean id="shibboleth.DefaultRelyingParty" parent="RelyingParty">

	<!-- Require MFA with Shibboleth SSO profile. -->
	<bean parent="Shibboleth.SSO">
		<property name="defaultAuthenticationMethods">
			<list>
				<ref bean="MFASAML1Principal" />
			</list>
		</property>
	</bean>

	<!-- Require MFA with SAML 2 SSO profile. -->
	<bean parent="SAML2.SSO" p:disallowedFeatures-ref="SAML2.SSO.FEATURE_AUTHNCONTEXT">
		<property name="defaultAuthenticationMethods">
			<list>
				<ref bean="MFASAML2Principal" />
			</list>
		</property>
	</bean>

</bean>

Options common to SAML profiles:

Guidance

It isn't too common to need any of these options, and they should be changed only with care.

The signResponses default varies by profile, see the notes on the individual profile pages.

Options common to SAML 2.0 profiles:

Guidance

The encryption options are generally set correctly for each different profile; see the notes on the individual profile pages.

Note that when the conditions to encrypt various constructs evaluate to true, the IdP will fail the request if it is unable to perform the encryption, for whatever reason. This is overrideable using the encryptionOptional property, which allows the IdP to encrypt if it can but continue otherwise. If you carefully control your metadata sources, which you should do in any case, you should be able to trust that any SP lacking an encryption key is incapable of encryption anyway, making the property safe to enable.

The ignoreRequestSignatures option is an interoperability knob to deal with badly broken or incompetently operated services. Signed requests in some profiles, particularly SSO, are often pointless and are frequently used for no good reason. If the signer's code is broken, or even worse if they manage their key poorly and require constant flag days to update them, this allows the signature to be ignored and potentially the key to be bypassed so their incompetence doesn't impact your operations.

Options common to SAML profiles that may transmit messages via SAML Artifact (a pass by reference instead of value, followed by a callback).

Guidance

You shouldn't really need to modify this, as artifacts are rarely used anymore, and if they are, the default configuration suffices. The main reason you might change it is to switch a SAML 1.1 SSO configuration from Type 1 to Type 2 artifacts, but that's very obscure. If it ever comes up, we will provide an example.

With SAML 2.0, there is a valid case for customizing the configuration on a per-node basis by exposing dedicated resolution endpoints on each node, and making sure a node issues artifacts that will be resolved by that node. This is already exposed for you via the idp.artifact.endpointIndex property.

Options specific to the SAML 2.0 Browser SSO profile:

Guidance

The nameIDFormatPrecedence property is a common way of controlling the type of SAML NameIdentifier / NameID included in a response, a common requirement of many commercial services. It is in fact the only way to force the use of the ill-advised "urn:oasis:names:tc:SAML:1.1:nameid-format:unspecified" Format, which it must be noted is very rarely needed, despite frequent mis-documentation to the contrary.

In most cases, it is better to control the Format selected by including a <NameIDFormat> element in the SP's metadata. In the event that you don't control the metadata, you can inject the required element by applying a metadata filter.

Examples of nameIDFormatPrecedence property

<bean id="shibboleth.DefaultRelyingParty" parent="RelyingParty">

	<!--
	Both constants below evaluate to the string "urn:oasis:names:tc:SAML:1.1:nameid-format:unspecified",
	and are interchangeable, they're just illustrations of different ways to reference the same string.
	-->

	<!-- Use "unspecified" NameIdentifier with Shibboleth SSO profile. -->
	<bean parent="Shibboleth.SSO">
		<property name="nameIDFormatPrecedence">
			<list>
				<util:constant static-field="org.opensaml.saml.saml1.core.NameIdentifier.UNSPECIFIED" />
			</list>
		</property>
	</bean>

	<!-- Use "unspecified" NameID with SAML 2 SSO profile. -->
	<bean parent="SAML2.SSO">
		<property name="nameIDFormatPrecedence">
			<list>
				<util:constant static-field="org.opensaml.saml.saml2.core.NameIDType.UNSPECIFIED" />
			</list>
		</property>
	</bean>

	<!-- Return formats from a function bean (not shown). -->
	<bean parent="Shibboleth.SSO" p:nameIDFormatPrecedenceLookupStrategy-ref="FormatsFunction" />

</bean>

The skipEndpointValidationWhenSigned option is attractive in many enterprise scenarios if you prefer to maintain some degree of security but avoid registration of metadata containing every individual SP endpoint, which adds a lot of overhead in massively vhosted-environments. It can also add a degree of insulation from SP changes, but in practice systems that are likely to change endpoint locations but don't support metadata-based change control are likely to misunderstand the need to keep entityIDs stable also.

The ignoreScoping setting is provided to work around interoperability issues with broken SPs.

Several other new settings are used when proxying and provide various kinds of policy controls familiar to SP operators, as well as new features to support remapping of potentially non-interoperable AuthnContext values. By default, the IdP operates in a fairly automatic fashion when proxying, such that any <saml2p:RequestedAuthnContext> element from an SP will be echoed essentially as-is to any upstream Identity Provider, and the data found in the incoming assertion will be echoed as-is back downstream. Since proxying is often used to firewall against interoperability problems and crosswalk between different communities of practice, functions can be plugged in to perform more flexible mapping of values, and some pre-existing machinery is in place to support this declaratively, as described in the AuthenticationConfiguration page. An additional hook was added in V4.1 that allows a similar function to be injected but with access to the entire request state to do more advanced things.

There are also a variety of settings related to delegation that are not shown above but can be found in the relevant API documentation.