Sunturai
Back to results
MediumElastic detection rulesElastic

AWS Lambda Function Invoked from an Unusual Source ASN

Identifies an AWS Lambda function invoked directly by a principal from a source network (ASN) not seen for that principal in the prior 10 days, excluding common cloud provider networks. Direct invocation from an…

Description

Identifies an AWS Lambda function invoked directly by a principal from a source network (ASN) not seen for that principal in the prior 10 days, excluding common cloud provider networks. Direct invocation from an unfamiliar external network can indicate use of stolen execution-role or user credentials from attacker-controlled infrastructure to execute functions or retrieve the data they return. This rule relies on AWS Lambda data event logging, which is not enabled by default.

Detection logic

Its licence does not clear it for publishing here

Sunturai publishes a detection's own text where the licence it arrived under has been reviewed and permits it, and Elastic License 2.0 has not. The query as its source wrote it, its canonical form and the hash that pins this revision are in the workspace record.

Sign in to read itCreate an account

Detection requirements

Platform
IaaSOffice SuiteSaaS

The rule states no platform. This is derived from the ATT&CK technique it maps to.

Log source category
event_index

Known benign triggers

  • Operators and automation may legitimately invoke functions from new networks (new offices, VPNs, home IPs, or new egress infrastructure). Verify the principal in `aws.cloudtrail.user_identity.arn`, the source network, and the function, and exclude known operator networks or identities after validation.

Detections can measure how the public catalogue is used — which detections people look for, and which pages bring them here. It sets a cookie that recognises this browser for 180 days. It is never linked to an account and never follows you to other sites. Privacy notice