SecurityConfiguration

File(s): conf/credentials.xml, conf/relying-party.xml, conf/idp.properties
Format: Native Spring, Property files.

1 Overview
2 General Topics
3 Reference
4 Notes

Overview

There are multiple aspects of configuration that fall under the heading of security:

credentials (keys and certificates)
configuration and control of algorithms to use for signing or encryption (as well as verifying signatures and decryption)
"TrustEngines" used to evalate signatures and certificates during message processing
other steps that run during profile execution to evaluate messages

All of these settings are associated with profile or relying party behavior, so most of them are configured as part of the more general RelyingPartyConfiguration service, and as such are reloaded when that service is reloaded.

General Topics

In most cases, it's not necessary to modify your credential configuration except to ensure the idp.properties settings that identify keys and certificates are set correctly, which is true after an installation when using the automatically generated credentials. The actual beans that load these files are in credentials.xml and have the following required names:

shibboleth.DefaultSigningCredential
shibboleth.DefaultClientTLSCredential
shibboleth.DefaultEncryptionCredentials

The first two are instances of the Credential class and specify the default keypair to use for signing and client TLS respectively. Client TLS isn't common, but may occur in rare instances such as inbound HTTP-Artifact binding messages or in future features such as outbound SOAP logout messages.

The third is a list that contains one or more instances of that same class, used for encryption (actually for decryption; this is the public key used to encrypt data for the IdP and the private key to decrypt it with).

If all you need is a single keypair for each function, then nothing needs to be done to this file. This is the strongly recommended approach. If you need to create additional signing credentials to use as overrides to behavior for specific relying parties, you may want to copy the existing bean and assign it a different id to refer to later (see below under Signing and Encryption).

In the event that you want to perform a controlled rollover of an encryption keypair, that involves the configuration of multiple keypairs (old and new) into the IdP, and this is accomodated with pre-existing definitions you can use by uncommenting the second keypair bean in the list and setting a second set of properties to point to the keypair. Support for decrypting with either key will be handled automatically when both are configured.

Mechanisms exist for defining advanced Credentials and are discussed here.

Enablement

For most situations, the default behavior of each ProfileConfiguration is appropriate when it comes to what to sign or encrypt. A common use case for creating overrides for particular relying parties is to either turn off XML Encryption, or possibly alter which part of a SAML message is to be signed. This is controlled with a set of properties on all SAMLProfileConfiguration and SAML2ProfileConfiguration objects, each of which is a condition that evaluates to true or false to determine what to sign or encrypt.

In most cases, you can set the properties to "true" or "false" to turn them on or off. An example follows:

Per-Profile Signing or Encryption Options

<!-- excerpt of relying-party.xml -->

<bean parent="RelyingPartyByName" c:relyingPartyIds="https://sp.example.org">
    <property name="profileConfigurations">
        <list>
            <bean parent="SAML2.SSO" p:signAssertions="true" p:encryptAssertions="false" />
        </list>
    </property>
</bean>

For more advanced scenarios, you can configure an arbitrary condition function to control the decision. Most commonly this would be used in conjunction with a built-in condition that works by deciding whether to sign or encrypt based on the security of the underlying communication channel. This isn't typically needed, but an example follows:

Conditional Signing or Encryption

<!-- excerpt of relying-party.xml -->

<bean id="SignNoIntegrity" class="org.opensaml.profile.logic.NoIntegrityMessageChannelPredicate" />
<bean id="EncryptNoConfidentiality" class="org.opensaml.profile.logic.NoConfidentialityMessageChannelPredicate" />

<bean parent="RelyingPartyByName" c:relyingPartyIds="https://sp.example.org">
    <property name="profileConfigurations">
        <list>
            <bean parent="SAML2.SSO" p:signAssertions-ref="SignNoIntegrity"
                p:encryptAssertions-ref="EncryptNoConfidentiality" />
        </list>
    </property>
</bean>

Finally, a new feature exists to do encryption "opportunistically", that is, to encrypt whenever possible (meaning a compatible key is found in the peer's metadata to encrypt with) but to skip encryption otherwise. For those wishing to avoid having to constantly adapt their system to deal with new services that don't support encryption, this is an option you can use, understanding that this means a loss of explicit control over whether XML Encryption takes place. This feature is enabled with the idp.encryption.optional property.

Configuration

There are several levels of SecurityConfiguration objects to control the signing, validation, encryption, and decryption processes. These configurations include things like the keypairs to use, preferred/default algorithms, and algorithm allow or deny lists to enforce. The configurations can be derived from the underlying library defaults, a global IdP default, or a per-profile override.

In most cases you will leave the defaults in place, or very occasionally define a special configuration to use for specific profiles and/or relying parties.

The default objects that make up these configurations are defined in a system file and are defined to match the defaults in the OpenSAML libraries. You can't modify these beans, but they do document the full range of wiring up of settings that's possible. You can inherit from some of them in order to override specific bits and leave the other defaults in place, which is simpler than creating an entire SecurityConfiguration object from scratch.

You can override the default bean name that is used as a global default by setting the idp.security.config property. That effectively ignores the system-defined objects in favor of something else. You can also override this on a per-profile, per-relying-party basis by adding a p:securityConfiguration-ref attribute to a profile bean.

The (formerly common) case of controlling the use of SHA-1 and SHA-256 digest algorithms while signing is simplified because we have predefined beans that toggle between those two algorithms at a global level, with a property to switch between them (idp.signing.config).

Similarly, there are predefined beans for toggling between two data encryption families, AES-CBC and AES-GCM. The former is widespread and well-supported, and vulnerable to attacks that can reveal the data. The latter is not widely supported but is the only practical algorithm that remains secure. A new property will switch between them globally (idp.encryption.config) but in practice that won't work all that well because so many SPs will not support GCM (though that should be considered non-compliant with any modern support for the standard).

The following is an example to follow if you need to specify the use of SHA-1 instead of SHA-256 for a specific relying party.

Per-Profile Signing Algorithm

<!-- excerpt of relying-party.xml -->

<util:list id="shibboleth.RelyingPartyOverrides">

  <bean parent="RelyingPartyByName" c:relyingPartyIds="https://sha1only.example.org">
    <property name="profileConfigurations">
        <list>
            <bean parent="Shibboleth.SSO" p:securityConfiguration-ref="shibboleth.SecurityConfiguration.SHA1" />
            <bean parent="SAML1.AttributeQuery" p:securityConfiguration-ref="shibboleth.SecurityConfiguration.SHA1" />
            <bean parent="SAML1.ArtifactResolution" p:securityConfiguration-ref="shibboleth.SecurityConfiguration.SHA1" />
            <bean parent="SAML2.SSO" p:securityConfiguration-ref="shibboleth.SecurityConfiguration.SHA1" />
            <bean parent="SAML2.ECP" p:securityConfiguration-ref="shibboleth.SecurityConfiguration.SHA1" />
            <bean parent="SAML2.Logout" p:securityConfiguration-ref="shibboleth.SecurityConfiguration.SHA1" />
            <bean parent="SAML2.AttributeQuery" p:securityConfiguration-ref="shibboleth.SecurityConfiguration.SHA1" />
            <bean parent="SAML2.ArtifactResolution" p:securityConfiguration-ref="shibboleth.SecurityConfiguration.SHA1" />
        </list>
    </property>
  </bean>

</util:list>

Similarly, you can do the same with encryption for GCM:

Per-Profile Encryption Algorithm

A more advanced case: to specify a custom keypair for signing for a particular relying party, you might create a bean in credentials.xml called "ObnoxiousVendorCredential", and then do the following (there are many ways to lay things out, this is just an example of what's possible):

Per-Profile Credential

Typically you want to think about what you need to customize, and then consolidate definitions of beans as much as possible to simplify the XML.

TrustEngines are a type of object used to evaluate signatures and TLS certificates and make up the security backbone of the IdP. This defaults to a "chain" of two strategies:

looking for a matching public key inside SAML metadata corresponding to a message issuer
verifying a certificate indirectly by performing PKIX path validation, generally against trust rules supplied in SAML metadata extensions defined by the Shibboleth Project many years ago

The recommended approach is the first one. The second is provided solely for compatibility and while it is used by some deployers, we expect to eventually disable it by default in a future release. It is not deprecated, but it is not a recommended choice.

In the event that you wish to replace the "chain" with a reference to one of the TrustEngines alone, you can set one or both of the idp.trust.signatures and idp.trust.certificates properties in idp.properties to appropriate bean names (noted below and in the property file's comments).

The last area of security configuration involves the steps to follow after a message is received to check the content and perform steps like replay detection, freshness detection, signature checking, evaluation of client certificate authentication for server to server communication, etc. This is also where profiles that require authentication of the request, such as Attribute Queries, enforce that requirement.

Internally, these rules are run as part of something called the inboundInterceptorFlows collection, which is a list of "interceptor" webflows to run before accepting a request for further processing. While this is in principle an extensible feature, in most cases you don't need to even think about this mechanism, and it's configured for you for all the built-in profile beans to do the "right" thing, provided you inherit any custom profile beans you want to use for overrides from the built-in beans listed in the RelyingPartyConfiguration (e.g., "Shibboleth.SSO", "SAML2.AttributeQuery").

Normally you need never customize these flows directly, other than via a few properties defined for that purpose, such as idp.policy.messageLifetime.

Reference

Properties defined in idp.properties directly related to this configuration area follow:

Property / Type / Default	Default	Function

Property / Type / Default	Default	Function
idp.cookie.secure Boolean	false	If true, all cookies issued by the IdP (not including the container) will be limited to TLS
idp.cookie.httpOnly Boolean	true	If true, all cookies issued by the IdP (not including the container) will contain the HttpOnly property
idp.cookie.domain String		Overrides the domain of any cookies issued by the IdP, not including the container
idp.cookie.path String		Overrides the path of any cookies issued by the IdP, not including the container
idp.cookie.maxAge Integer	31536000 (1 year)	Lifetime in seconds of cookies issued by the IdP that are meant to span sessions (365 days)
idp.cookie.sameSite "Null", "None", "Lax", or "Strict"	"None"	Default SameSite value to apply to cookies via servlet filter if no explicit rule for the named cookie is specified
idp.cookie.sameSiteCondition Bean ID of Predicate<ServletRequest>	shibboleth.Conditions.FALSE	Predicate<ServletRequest> condition bean controlling whether SameSite filter runs
idp.sealer.keyStrategy Bean ID of DataSealerKeyStrategy	shibboleth.DataSealerKeyStrategy	Bean ID supporting the DataSealerKeyStrategy interface to use in place of the built-in option.
idp.sealer.storeType String	"JCEKS"	Type of Java keystore used for IdP's internal AES encryption key
idp.sealer.updateInterval Duration	PT15M	Time between checks for a new AES key version
idp.sealer.aliasBase String	"secret"	Case insensitive name of keystore alias prefix used in AES keystore (the entries will be suffixed by the key version number)
idp.sealer.storeResource Resource path		Keystore resource containing AES encryption key, usually a file path
idp.sealer.versionResource Resource path		Resource that tracks the "active" AES encryption key version, usually a file path
idp.sealer.storePassword String		Keystore password unlocking AES encryption keystore, typically set during installation
idp.sealer.keyPassword String		Key password unlocking AES encryption key, typically set to the same as the previous property and set during installation
idp.signing.key Resource path		Resource containing private key for signing, typically a file in the credentials directory
idp.signing.cert Resource path		Resource containing the public key certificate inserted into signed messages, typically a file in the credentials directory
idp.encryption.key Resource path		Resource containing a private key for decryption, typically a file in the credentials directory
idp.encryption.cert Resource path		Resource containing a public key certificate given to others needing to encrypt data for the IdP, typically a file in the credentials directory
idp.encryption.key.2 Resource path		Resource containing an alternate private key for decryption, generally unused except while changing decryption keys
idp.encryption.cert.2 Resource path		Resource containing an alternate public key certificate, generally unused except while changing decryption keys
idp.security.config Bean ID of SecurityConfiguration	shibboleth.DefaultSecurityConfiguration	Name of Spring bean supplying the default SecurityConfiguration
idp.signing.config Bean ID of SignatureSigningConfiguration	shibboleth.SigningConfiguration.SHA256	Name of Spring bean supplying the default SignatureSigningConfiguration
idp.encryption.config Bean ID of EncryptionConfiguration	shibboleth.EncryptionConfiguration.CBC	Name of Spring bean supplying the default EncryptionConfiguration
idp.trust.signatures Bean ID of SignatureTrustEngine	shibboleth.ChainingSignatureTrustEngine	Name of Spring bean for the trust engine used to verify signatures
idp.trust.certificates Bean ID of TrustEngine	shibboleth.ChainingX509TrustEngine	Name of Spring bean for the trust engine used to verify TLS certificates
idp.encryption.optional Boolean	false	If true, failure to locate an encryption key to use, when enabled, won't result in request failure
idp.errors.detailed Boolean	false	If true, more detailed error information may be returned in profile responses, which could leak useful information in rare cases
idp.errors.signed Boolean	true	When message signing is enabled, controls whether to sign responses that signal errors as opposed to successful outcomes
idp.policy.messageLifetime Duration	PT3M	Default freshness window for accepting timestamped messages
idp.policy.assertionLifetime Duration	PT3M	Default freshness window for accepting timestamped assertions
idp.policy.clockSkew Duration	PT3M	Default allowance for clock differences between systems
idp.artifact.secureChannel Boolean	true	If true, skips signing/encryption when the message will be passed by reference (via artifact in SAML terms)
idp.security.basicKeyInfoFactory ^4.1 Bean ID of KeyInfoGeneratorManager	shibboleth.BasicKeyInfoGeneratorFactory	Overrides the BasicKeyInfoGeneratorFactory used by default
idp.security.x509KeyInfoFactory ^4.1 Bean ID of KeyInfoGeneratorManager	shibboleth.X509KeyInfoGeneratorFactory	Overrides the X509KeyInfoGeneratorFactory used by default

Notes

The IdP defaults to the use of separate keypairs for signing and decryption, the latter being a capability that is rarely used at present and primarily comes into play only when processing <LogoutRequest> messages that contain an encrypted subject ID.

The default algorithms used have been updated to:

RSA or ECDSA (depending on key type) with SHA-256 digests
AES-GCM-128 with RSA-OAEP-MGF1 key transport

The IdP also supports a standardized SAML metadata extension that influences the algorithms it will use, based on the capabilities of the SP. For metadata under your control, using the extension to specify that SHA-1 is required is generally a better strategy than specifying it in a RelyingParty override, but often this isn't possible, so a filter is also provided for supplementing remote sources. We encourage deployers to ask their metadata sources (i.e., federations) about this capability, as it is critically important for dealing with future algorithm weaknesses that may emerge over time.