403 intermittently on public lambda URL invocation

Question

Good day,

We have 2 lambda functions with public URLs hosted in eu-west-1 AZ both set to Auth: NONE

These URL's have been operating fine for months now without any further changes from our side.

Since the early hours of this morning we are intermittently getting a 403 response from both lambdas:

X-Amzn-Errortype: IncompleteSignatureException

Is anyone else experiencing this issue, I've tried re-deploying both lambdas without any success.

Accepted Answer

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On July 4, 2023 at approximately 11:00 PM PDT (July 5, 2023 6am UTC), we became aware of an issue where a subset of customers began experiencing an increase in 403 errors when invoking function URLs in the EU-WEST-1 Region. The underlying issue has been addressed and changes to resolve the issue are currently being deployed. We expect to see recovery by July 5, 2023 at 6:00 AM PDT (1pm UTC). We do not require any additional actions from customers at this time.
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thanks for your input David!

Answer

Yes CORS and resource policies set on both and nothing has changed in months in respect of this.

The fact that its working intermittently, I would say about 10% of the calls, leads me to believe this is some sort of AWS internal issue..

Answer

If you have a high amount of request you can use reserved concurrency - https://docs.aws.amazon.com/lambda/latest/dg/configuration-concurrency.html

Answer

Do you have any Resource Policies?

https://docs.aws.amazon.com/lambda/latest/dg/access-control-resource-based.html

Do you have any CORS set on the Lmabdas?

https://docs.aws.amazon.com/lambda/latest/dg/API_Cors.html

Best David

403 intermittently on public lambda URL invocation

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