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Authentication mechanism absence or evasion - AWS

Need​

Implementation of a robust and secure authentication mechanism for AWS

Context​

  • Usage of Terraform for infrastructure as code provisioning and management
  • Usage of AWS SDK for interacting with Amazon Web Services

Description​

Non compliant code​

provider "aws" {
  region = "us-west-2"
}

The above Terraform code is used to set up an AWS provider without any authentication mechanism. This is a significant security vulnerability as it allows anyone to access and manipulate the AWS infrastructure.

In this scenario, the AWS provider is set to the us-west-2 region but no authentication details are provided. This means that Terraform will attempt to use default credentials sources, including environment variables or default AWS CLI configurations. If these are not securely managed or are absent, it could lead to unauthorized access to the AWS resources.

Terraform supports several ways of providing these credentials (Environment variables, Shared credentials file, etc.). The absence of these mechanisms in the code means that the code is relying on the default AWS CLI configurations. If these configurations are not properly secured, it can lead to a serious security breach.

Also, if the credentials can be easily bypassed, it poses another security risk. For example, if the AWS credentials are hardcoded in the code and the code is shared publicly, anyone can use these credentials to gain access to the AWS resources.

Overall, the absence of a secure authentication mechanism or the presence of an easily bypassable one in the AWS configuration is a serious security vulnerability that needs to be addressed.

Steps​

  • Choose an appropriate AWS authentication mechanism based on your business security requirements.
  • Configure the chosen authentication mechanism in the AWS provider block.
  • Ensure that the authentication mechanism is properly implemented and cannot be bypassed.
  • Test the authentication mechanism to verify its effectiveness.
  • Regularly review and update the authentication mechanism as needed to maintain the security of your AWS infrastructure.

Compliant code​

provider "aws" {
  region     = "us-west-2"
  access_key = "my-access-key"
  secret_key = "my-secret-key"
}

The original code was vulnerable due to the absence of an authentication mechanism. The AWS provider was only configured with a region, but no access key or secret key was provided. This means that anyone could potentially interact with your AWS resources without any form of authentication.

The fixed code now includes an access_key and secret_key in the AWS provider block. These are used to authenticate with AWS and ensure that only authorized users can interact with your AWS resources.

Please replace "my-access-key" and "my-secret-key" with your actual AWS access key and secret key.

Note: Storing your AWS credentials in your Terraform configuration is not recommended. Instead, consider using Environment Variables or the AWS Shared Credentials file for more secure credential management.

Remember to never expose your access_key and secret_key in your public repositories, it's a security risk. Always use secure and encrypted methods to store and retrieve your keys.

After implementing the authentication mechanism, ensure to test it to verify its effectiveness. Regularly review and update the authentication mechanism as needed to maintain the security of your AWS infrastructure.

References​

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