SAML LogOutRequest processing failed on ADFS server - saml

Question

I have ADFS server as an IdP. I have separate SP application. These are defined in circle of trust. SSO over SAML protocol is working fine. When I try SP initated log out request I got error on ADFS side :
MSIS7000: The sign in request is not compliant to the WS-Federation language for web browser clients or the SAML 2.0 protocol WebSSO profile.
EDIT More detail message from ADFS Event Trace :
MSIS7015: This request does not contain the expected protocol message or incorrect protocol parameters were found according to the HTTP SAML protocol bindings.
I have reviewed mu log out SAML message and looks correct. Just to mention that same SP is loging out properly with ForgeRocks IdP (ex Sun OpenSSO).
Saml loout request message :
<samlp:LogoutRequest xmlns:samlp="urn:oasis:names:tc:SAML:2.0:protocol"
ID="b00b3f55-f3e3-4935-9e91-da6bf8b62efd"
Version="2.0"
IssueInstant="2013-08-27T09:45:08Z"
Destination="https://00.00.00.00/adfs/ls/"
Consent="urn:oasis:names:tc:SAML:2.0:consent:unspecified"
NotOnOrAfter="2013-08-27T09:50:08Z"
>
<saml:Issuer xmlns:saml="urn:oasis:names:tc:SAML:2.0:assertion">SPEntityId/</saml:Issuer>
<saml:NameID xmlns:saml="urn:oasis:names:tc:SAML:2.0:assertion" Format="urn:oasis:names:tc:SAML:1.1:nameid-format:unspecified">jsmith#company.com</saml:NameID>
<samlp:SessionIndex>_ea853497-c58a-408a-bc23-c849752d9741</samlp:SessionIndex>
EDIT
Lan suggested to me that signing of the logout request messages is mandatory. He was right. In OASIS specification (http://docs.oasis-open.org/security/saml/v2.0/saml-profiles-2.0-os.pdf) section 4.4.3.1. it is described. According with that I am sending now signed messages but I am having the same issue.
Signed message :
<samlp:LogoutRequest xmlns:samlp="urn:oasis:names:tc:SAML:2.0:protocol"
ID="aed640c0-9455-49ea-9450-4ad7c08d98e7"
Version="2.0"
IssueInstant="2013-08-29T15:22:45Z"
Destination="https://server/adfs/ls/"
Consent="urn:oasis:names:tc:SAML:2.0:consent:unspecified"
NotOnOrAfter="2013-08-29T03:27:45Z"
>
<saml:NameID xmlns:saml="urn:oasis:names:tc:SAML:2.0:assertion"
Format="urn:oasis:names:tc:SAML:2.0:nameid-format:transient">user</saml:NameID>
<samlp:SessionIndex>_677952a2-7fb3-4e7a-b439-326366e677db</samlp:SessionIndex>
<saml:Issuer xmlns:saml="urn:oasis:names:tc:SAML:2.0:assertion">SPIssuer</saml:Issuer>
<Signature xmlns="http://www.w3.org/2000/09/xmldsig#">
<SignedInfo>
<CanonicalizationMethod Algorithm="http://www.w3.org/TR/2001/REC-xml-c14n-20010315" />
<SignatureMethod Algorithm="http://www.w3.org/2000/09/xmldsig#rsa-sha1" />
<Reference URI="#aed640c0-9455-49ea-9450-4ad7c08d98e7">
<Transforms>
<Transform Algorithm="http://www.w3.org/2000/09/xmldsig#enveloped-signature" />
</Transforms>
<DigestMethod Algorithm="http://www.w3.org/2000/09/xmldsig#sha1" />
<DigestValue>53jjPvQ2Ty1Z+VikwrUwW4Erj3k=</DigestValue>
</Reference>
</SignedInfo>
<SignatureValue>signed value</SignatureValue>
<KeyInfo>
<X509Data>
<X509Certificate>certificate</X509Certificate>
</X509Data>
</KeyInfo>
</Signature>
What I am doing wrong ? Should be specified some other endpoint on ADFS ? As I got is should be used same as for sign on requests (that are working perfectly on my side).
Thanks,
Rastko

Answer 1

Finlay I can do SLO :)
Previously I have worked with ForgeRock's IDP and it worked perfectly, but with ADFS did not. It is obvious that Microsoft has restricted rules related with SAML message formatting. Conclusions that I have found :
LogoutRequest message MUST be signed (SAML 2.0 Profiles doc, Sect 4.4.3.1). Thank you Ian for this.
Order of the XML elements and attributes is important. On the bottom of this message is final version of my log out request.
NameId must be in the same format as one received from AuthenticationResponse. It should contains elements expected by ADFS. These links helped me : Name Identifier (Name ID) claim in the SAML subject and SAML LogoutRequest
LogoutRequest signature must me transformed with XmlDsigExcC14NTransform, that should be added after XmlDsigEnvelopedSignatureTransform
Canonization method for signing should be http://www.w3.org/2001/10/xml-exc-c14n#
Issuer, NameID and SessionIndex are mandatory XML elements
Namespaces are mandatory : xmlns:samlp="urn:oasis:names:tc:SAML:2.0:protocol" and xmlns:saml="urn:oasis:names:tc:SAML:2.0:assertion"
Final LogoutRequest message that is working :
<samlp:LogoutRequest ID="f8a62847-92f2-4f0c-936a-df9efe0cc42f"
Version="2.0"
IssueInstant="2013-08-29T20:53:50Z"
Destination="https://server/adfs/ls/"
Consent="urn:oasis:names:tc:SAML:2.0:consent:unspecified"
xmlns:samlp="urn:oasis:names:tc:SAML:2.0:protocol"
>
<saml:Issuer xmlns:saml="urn:oasis:names:tc:SAML:2.0:assertion">https://sp.com/</saml:Issuer>
<Signature xmlns="http://www.w3.org/2000/09/xmldsig#">
<SignedInfo>
<CanonicalizationMethod Algorithm="http://www.w3.org/2001/10/xml-exc-c14n#" />
<SignatureMethod Algorithm="http://www.w3.org/2000/09/xmldsig#rsa-sha1" />
<Reference URI="#f8a62847-92f2-4f0c-936a-df9efe0cc42f">
<Transforms>
<Transform Algorithm="http://www.w3.org/2000/09/xmldsig#enveloped-signature" />
<Transform Algorithm="http://www.w3.org/2001/10/xml-exc-c14n#" />
</Transforms>
<DigestMethod Algorithm="http://www.w3.org/2000/09/xmldsig#sha1" />
<DigestValue>W7F1E2U1OAHRXn/ItbnsYZyXw/8=</DigestValue>
</Reference>
</SignedInfo>
<SignatureValue></SignatureValue>
<KeyInfo>
<X509Data>
<X509Certificate></X509Certificate>
</X509Data>
</KeyInfo>
</Signature>
<saml:NameID xmlns:saml="urn:oasis:names:tc:SAML:2.0:assertion"
Format="http://schemas.xmlsoap.org/claims/UPN"
>user</saml:NameID>
<samlp:SessionIndex>_2537f94b-a150-415e-9a45-3c6fa2b6dd60</samlp:SessionIndex>

Answer 2

IIRC SAML 2.0 SP-Initiated SLO requires the use of Digital Signatures on the LogoutRequest? This ensures that no one spoofs the LogoutRequest and logs a user out of all their existing sessions.
Assuming you are using the POST binding and not Redirect since I can't see the Signature in the XML. With Redirect the Signature info is passed as a query parameter.