Untrusted JWT Signatures Can Bypass Authentication in ALB

CVE-2024-8901

What is CVE-2024-8901?

The AWS ALB Route Directive Adapter For Istio repo https://github.com/awslabs/aws-alb-route-directive-adapter-for-istio/tree/master provides an OIDC authentication mechanism that was integrated into the open source Kubeflow project. The adapter uses JWT for authentication, but lacks proper signer and issuer validation. In deployments of ALB that ignore security best practices, where ALB targets are directly exposed to internet traffic, an actor can provide a JWT signed by an untrusted entity in order to spoof OIDC-federated sessions and successfully bypass authentication.

The repository/package has been deprecated, is end of life, and is no longer supported. As a security best practice, ensure that your ELB targets (e.g. EC2 Instances, Fargate Tasks etc.) do not have public IP addresses. Ensure any forked or derivative code validate that the signer attribute in the JWT match the ARN of the Application Load Balancer that the service is configured to use.

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