Elastic Security Detection Rules

AWS Lambda Function Policy Updated to Allow Public Invocation

Last updated 7 months ago on 2025-01-15
Created a year ago on 2024-04-30

About

Identifies when an AWS Lambda function policy is updated to allow public invocation. This rule specifically looks for the `AddPermission` API call with the `Principal` set to `*` which allows any AWS account to invoke the Lambda function. Adversaries may abuse this permission to create a backdoor in the Lambda function that allows them to execute arbitrary code.
Tags
Domain: CloudData Source: AWSData Source: Amazon Web ServicesData Source: AWS LambdaUse Case: Threat DetectionTactic: PersistenceLanguage: kuery
Severity
medium
Risk Score
47
MITRE ATT&CK™

Persistence (TA0003)(opens in a new tab or window)

↳ Event Triggered Execution (T1546)(opens in a new tab or window)

False Positive Examples
Lambda function owners may legitimately update the function policy to allow public invocation.
License
Elastic License v2(opens in a new tab or window)

Definition

Rule Type
Query (Kibana Query Language)
Integration Pack
Prebuilt Security Detection Rules
Index Patterns
filebeat-*logs-aws.cloudtrail-*
Related Integrations

aws(opens in a new tab or window)

Query
event.dataset: aws.cloudtrail
    and event.provider: lambda.amazonaws.com
    and event.outcome: success
    and event.action: AddPermission*
    and aws.cloudtrail.request_parameters: (*lambda\:InvokeFunction* and *principal=\**)

Install detection rules in Elastic Security

Detect AWS Lambda Function Policy Updated to Allow Public Invocation in the Elastic Security detection engine by installing this rule into your Elastic Stack.

To setup this rule, check out the installation guide for Prebuilt Security Detection Rules(opens in a new tab or window).