AWS Lambda Function resource-based policy is overly permissive misconfiguration detected in code

Rule Details

Cortex AppSec Rule ID	APPSEC_AWS_301
Category - Subcategory	IAM - Overly Permissive
Provider	AWS
Severity	LOW
Framework	Terraform, Terraform Plan
Mapped CSPM/KSPM Rule	dc0d3fb7-4c3e-4930-b68b-931908d36d71

Impact

This rule is examining AWS Lambda functions to ensure they aren't publicly accessible. Having AWS Lambda functions that can be accessed by anyone can lead to sinister activities such as data theft, data manipulation, or other forms of unauthorized access. It's considered bad practice and a security risk, as it allows any anonymous user to invoke the function, potentially leading to misuse of the function or exposure of sensitive information. Therefore, it's important to have controls on who can execute the function, for example, authenticated or identified users only.

How to Fix

Resource: aws_lambda_permission

• Arguments: principal

To fix this issue, ensure the AWS Lambda function is not publicly accessible by restricting access to trusted entities only. Set 'principal' to a specific AWS resource or user-account other than '*'. [source,go]

resource "aws_lambda_permission" "with_s3" { statement_id = "AllowExecutionFromS3Bucket" action = "lambda:InvokeFunction" function_name = aws_lambda_function.example.function_name

• principal = "*" source_arn = "arn:aws:s3:::example_bucket" }

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