Splunk Enterprise

What is this Azure SAML request error AADSTS7500529?


Hi all,

I'm configuring Splunk (Docker image 8.1.0) to make SAML authentication on Azure ADFS.

Despite all looks right, I get this error in response to the Splunk SAML Request











'AADSTS7500529: The value '1a480d8dd87f.4.DA3C17FD-8DE5-4E39-8F52-5EF91CD63A51' is not a valid SAML ID. The ID must not begin with a number.'

I guess a problem with the ID's format of <samlp:AuthnRequest>, let me show you the content of my SAML requests



<samlp:AuthnRequest xmlns:saml="urn:oasis:names:tc:SAML:2.0:assertion" xmlns:samlp="urn:oasis:names:tc:SAML:2.0:protocol" ID="1a480d8dd87f.3.DA3C17FD-8DE5-4E39-8F52-5EF91CD63A51" 



Whereas Microsoft SAML 2.0 protocol documentation  impose a specific format for it

ID Required Azure AD uses this attribute to populate the InResponseTo attribute of the returned response. ID must not begin with a number, so a common strategy is to prepend a string like "id" to the string representation of a GUID. For example, id6c1c178c166d486687be4aaf5e482730 is a valid ID.


Do you confirm this is a malfunction ?



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I just worked my way through this issue. 

The SAML ID is prefixed with the hostname of the docker container. Which in my case was auto-generated starting with a number. When I consoled into my container and ran cat /etc/hostname I could see the mysterious number that was breaking my SAML auth with:

'AADSTS7500529: The value '1a480d8dd87f.4.DA3C17FD-8DE5-4E39-8F52-5EF91CD63A51' is not a valid SAML ID. The ID must not begin with a number.'

Where 1a480d8dd87f was my container hostname.

I re-deployed my docker stack with:

image: ${SPLUNK_IMAGE:-splunk/splunk:latest}
container_name: splunk
hostname: splunk

And my SAML began to work:


Hope this helps someone in the future 🙂 

~ James

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