OAuth 1.0 Signature Invalid When Targeting Magento URL in APIM

Question

OAuth 1.0 Signature Invalid When Targeting Magento URL in APIM

brahmateja ubbarapu 0

I have an API Management (APIM) service targeting a Magento URL with OAuth 1.0 authentication. However, I'm getting the error:

"The signature is invalid. Verify and try again."

The issue seems to be caused by the signature changing unexpectedly.

Has anyone encountered this before? Any suggestions on how to troubleshoot or fix it?

Ranashekar Guda 1,265 Reputation points Microsoft External Staff

2025-04-18T18:10:07.7766667+00:00

Hello @brahmateja ubbarapu,
When using Azure API Management (APIM) to connect to Magento's REST API with OAuth 1.0a, the error “The signature is invalid. Verify and try again.” is typically caused by how the OAuth signature is generated. Magento’s OAuth 1.0 implementation is highly sensitive to factors like parameter order, percent-encoding, URL formatting and the inclusion of empty parameters such as oauth_token=. So try this solution to offload OAuth signature generation to an external service, like an Azure Function, using a proper OAuth 1.0a library. This ensures strict compliance with OAuth standards and avoids subtle policy-level issues in APIM.

For further clarification, please refer to the following documentations:

https://github.com/magento/magento2/issues/37913

https://github.com/magento/magento2/issues/37278

https://github.com/magento/magento2/issues/33940
Hope this helps. Do let us know if you any further queries.
brahmateja ubbarapu 0 Reputation points

2025-04-20T05:20:17.5566667+00:00

Hello @Ranashekar Guda , Thank you for your response. Is there a way to do this without relying on an external service?
Ranashekar Guda 1,265 Reputation points Microsoft External Staff

2025-04-21T10:23:50.5866667+00:00

Hello @brahmateja ubbarapu,
To fix the "invalid signature" error with Magento OAuth 1.0 in APIM without an external service, you can either carefully construct the Authorization header using APIM policies or use a custom C# policy to leverage OAuth 1.0 libraries for accurate signature generation. Use APIM tracing and logging to troubleshoot by inspecting the generated header and intermediate values. Start with a basic policy and gradually add complexity. While challenging, these methods allow you to handle the signature directly within APIM.
brahmateja ubbarapu 0 Reputation points

2025-04-21T10:37:00.59+00:00

Hi @Ranashekar Guda , do you have any example or snippet to achieve this? please let me know if you have any.

brahmateja ubbarapu 0

@Ranashekar Guda, this is my policy

<policies>    <inbound>        <base />        <rewrite-uri template="/rest/all/V1/products" copy-unmatched-params="true" />		<set-backend-service base-url="https://mcstaging.com.au/index.php" />    </inbound>    <backend>        <base />    </backend>    <outbound>        <base />    </outbound>    <on-error>        <base />    </on-error></policies>

Ranashekar Guda 1,265 Reputation points Microsoft External Staff

2025-04-22T10:37:44.99+00:00

Hello @brahmateja ubbarapu,
You can generate an OAuth 1.0a signature within Azure API Management, but it can be quite complex. You'll need to manually set parameters like oauth_consumer_key, oauth_token, oauth_timestamp, and others using policy variables. The most challenging part is generating the oauth_signature, which requires strict parameter encoding, ordering, and HMAC-SHA1 hashing. While it's possible to do this entirely within APIM policies, it requires careful implementation. A more reliable approach is to use a C# policy or an Azure Function for signature generation. To help with troubleshooting, enable APIM tracing to inspect headers and debug the process.
Ranashekar Guda 1,265 Reputation points Microsoft External Staff

2025-04-23T12:05:32.3166667+00:00

Hi @brahmateja ubbarapu,
Just checking in to see if above information was helpful. If you have any further updates on this issue, please feel free to post back.

Your answer

Ranashekar Guda 1,265 Reputation points Microsoft External Staff

2025-04-18T18:10:07.7766667+00:00

Hello @brahmateja ubbarapu,
When using Azure API Management (APIM) to connect to Magento's REST API with OAuth 1.0a, the error “The signature is invalid. Verify and try again.” is typically caused by how the OAuth signature is generated. Magento’s OAuth 1.0 implementation is highly sensitive to factors like parameter order, percent-encoding, URL formatting and the inclusion of empty parameters such as oauth_token=. So try this solution to offload OAuth signature generation to an external service, like an Azure Function, using a proper OAuth 1.0a library. This ensures strict compliance with OAuth standards and avoids subtle policy-level issues in APIM.

For further clarification, please refer to the following documentations:

https://github.com/magento/magento2/issues/37913

https://github.com/magento/magento2/issues/37278

https://github.com/magento/magento2/issues/33940
Hope this helps. Do let us know if you any further queries.
brahmateja ubbarapu 0 Reputation points

2025-04-20T05:20:17.5566667+00:00

Hello @Ranashekar Guda , Thank you for your response. Is there a way to do this without relying on an external service?
Ranashekar Guda 1,265 Reputation points Microsoft External Staff

2025-04-21T10:23:50.5866667+00:00

Hello @brahmateja ubbarapu,
To fix the "invalid signature" error with Magento OAuth 1.0 in APIM without an external service, you can either carefully construct the Authorization header using APIM policies or use a custom C# policy to leverage OAuth 1.0 libraries for accurate signature generation. Use APIM tracing and logging to troubleshoot by inspecting the generated header and intermediate values. Start with a basic policy and gradually add complexity. While challenging, these methods allow you to handle the signature directly within APIM.
brahmateja ubbarapu 0 Reputation points

2025-04-21T10:37:00.59+00:00

Hi @Ranashekar Guda , do you have any example or snippet to achieve this? please let me know if you have any.
brahmateja ubbarapu 0 Reputation points

2025-04-21T15:31:02.9233333+00:00

@Ranashekar Guda, this is my policy

<policies> <inbound> <base /> <rewrite-uri template="/rest/all/V1/products" copy-unmatched-params="true" /> <set-backend-service base-url="https://mcstaging.com.au/index.php" /> </inbound> <backend> <base /> </backend> <outbound> <base /> </outbound> <on-error> <base /> </on-error></policies>
Ranashekar Guda 1,265 Reputation points Microsoft External Staff

2025-04-22T10:37:44.99+00:00

Hello @brahmateja ubbarapu,
You can generate an OAuth 1.0a signature within Azure API Management, but it can be quite complex. You'll need to manually set parameters like oauth_consumer_key, oauth_token, oauth_timestamp, and others using policy variables. The most challenging part is generating the oauth_signature, which requires strict parameter encoding, ordering, and HMAC-SHA1 hashing. While it's possible to do this entirely within APIM policies, it requires careful implementation. A more reliable approach is to use a C# policy or an Azure Function for signature generation. To help with troubleshooting, enable APIM tracing to inspect headers and debug the process.
Ranashekar Guda 1,265 Reputation points Microsoft External Staff

2025-04-23T12:05:32.3166667+00:00

Hi @brahmateja ubbarapu,
Just checking in to see if above information was helpful. If you have any further updates on this issue, please feel free to post back.

Share via

OAuth 1.0 Signature Invalid When Targeting Magento URL in APIM

Your answer