SAML Response xml not valid

Question

I have developed a custom SAML IdP for one of our clients. However when trying to pass the following response to the SP it fails. I tried validating the response using some of the SAML online tools available online and I see some errors but I can't figure out what's wrong. Can someone help please?

    <Response xmlns:xsd="http://www.w3.org/2001/XMLSchema"
      xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
      xmlns:ds="http://www.w3.org/2000/09/xmldsig#"
      xmlns:saml="urn:oasis:names:tc:SAML:2.0:assertion"
      ID="_8ad9eb0c-c65c-4327-ae76-ae238ca17e96"
      Version="2.0"
      IssueInstant="2017-06-28T13:53:06.9612024Z"
      Destination="https://crnm.lessonly.com/auth/saml/callback"
      xmlns="urn:oasis:names:tc:SAML:2.0:protocol"
      >
<saml:Issuer>https://crnm.lessonly.com/auth/saml/metadata</saml:Issuer>
<Status>
    <StatusCode Value="urn:oasis:names:tc:SAML:2.0:status:Success" />
</Status>
<saml:Assertion Version="2.0"
                ID="_4761e320-64e8-4d8a-a443-2e4e2ccb3e98"
                IssueInstant="2017-06-28T13:53:06.9612024Z"
                >
    <saml:Issuer>https://crnm.lessonly.com/auth/saml/metadata</saml:Issuer>
    <saml:Subject>
        <saml:NameID Format="urn:oasis:names:tc:SAML:1.1:nameid-format:emailAddress">[email protected]</saml:NameID>
        <saml:SubjectConfirmation Method="urn:oasis:names:tc:SAML:2.0:cm:bearer">
            <saml:SubjectConfirmationData Recipient="https://crnm.lessonly.com/auth/saml/callback"
                                          NotOnOrAfter="2017-06-28T13:58:06.9768269Z"
                                          />
        </saml:SubjectConfirmation>
    </saml:Subject>
    <saml:Conditions NotBefore="2017-06-28T13:53:06.9768269Z"
                     NotOnOrAfter="2017-06-28T13:58:06.9768269Z"
                     >
        <saml:AudienceRestriction>
            <saml:Audience>https://crnm.lessonly.com/auth/saml/metadata</saml:Audience>
        </saml:AudienceRestriction>
    </saml:Conditions>
    <saml:AuthnStatement AuthnInstant="2017-06-28T13:53:06.9768269Z"
                         SessionIndex="_4761e320-64e8-4d8a-a443-2e4e2ccb3e98"
                         >
        <saml:AuthnContext>
            <saml:AuthnContextClassRef>urn:oasis:names:tc:SAML:2.0:ac:classes:unspecified</saml:AuthnContextClassRef>
        </saml:AuthnContext>
    </saml:AuthnStatement>
    <saml:AttributeStatement>
        <saml:Attribute Name="UserID"
                        NameFormat="urn:oasis:names:tc:SAML:2.0:attrname-format:basic"
                        >
            <saml:AttributeValue xsi:type="xsd:string">125481</saml:AttributeValue>
        </saml:Attribute>
        <saml:Attribute Name="email"
                        NameFormat="urn:oasis:names:tc:SAML:2.0:attrname-format:basic"
                        >
            <saml:AttributeValue xsi:type="xsd:string">[email protected]</saml:AttributeValue>
        </saml:Attribute>
        <saml:Attribute Name="first_name"
                        NameFormat="urn:oasis:names:tc:SAML:2.0:attrname-format:basic"
                        >
            <saml:AttributeValue xsi:type="xsd:string">Angel1</saml:AttributeValue>
        </saml:Attribute>
        <saml:Attribute Name="last_name"
                        NameFormat="urn:oasis:names:tc:SAML:2.0:attrname-format:basic"
                        >
            <saml:AttributeValue xsi:type="xsd:string">Milev1</saml:AttributeValue>
        </saml:Attribute>
        <saml:Attribute Name="name"
                        NameFormat="urn:oasis:names:tc:SAML:2.0:attrname-format:basic"
                        >
            <saml:AttributeValue xsi:type="xsd:string">Angel1 Milev1</saml:AttributeValue>
        </saml:Attribute>
    </saml:AttributeStatement>
    <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="#_4761e320-64e8-4d8a-a443-2e4e2ccb3e98">
                <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>UB/5XN1dGa2/w0aKRmmq2oFvbOE=</DigestValue>
            </Reference>
        </SignedInfo>
        <SignatureValue>JTkUhfmk2ngPQnFtSC41WQodJj0MyCHw8oCJbEQE32vgViV4ucVvaim4jKMMD6B7JIkvCtuyu8II5h6oJOSsXQK0x03hlQFqpdgj/1Be53v9H90PWTgJ1mr41jF2AQTgAcdJmuV05oI23KxI+5jNFifri+POHSEfRU+k0Phyh+UTA2DlhFnbn5DAjzhnIu4e+L35QJBCSwZy7zT+NDr7dzL/JLAQOC79PlaM4cbjn9ri2bUwS3T1QFMQqsxGOl+ggaAwGWWNQlCV2Se2tZ1rLVUpZ5lB611GIbysBmghy5gtDe3htDHsp8IkuJnRf4lndjral7FVmZ1pdPhdK7HTgTA=</SignatureValue>
        <KeyInfo>
            <X509Data>
                <X509Certificate>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</X509Certificate>
            </X509Data>
        </KeyInfo>
    </Signature>
</saml:Assertion>
</Response>

using the validator on samltool.com I get the following error:

The XML is invalid.

Line: 69 | Column: 0 --> Element '{http://www.w3.org/2000/09/xmldsig#}Signature': This element is not expected.

Answer 1

The SAML XSD requires the Signature element to be just after the Issuer element