AWS ECS Task Definition That Queries The Credential Endpoint — Sigma Rule

Rule metadata and linked tags

Author: Darin Smith. Source status: test; severity: medium. Source dates: 2022-06-07 / 2023-04-24.

{
  "product": "aws",
  "service": "cloudtrail"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 4af2f599145bc049284a6f45d738b737e5e55b2f73b0baa539c25f8db1dfbd14

Detection logic

Original source YAML. Source-tag agreement is not proof of complete semantic coverage. This rule has not been compiled for a SIEM backend or validated against live telemetry here.

title: AWS ECS Task Definition That Queries The Credential Endpoint
id: b94bf91e-c2bf-4047-9c43-c6810f43baad
status: test
description: |
    Detects when an Elastic Container Service (ECS) Task Definition includes a command to query the credential endpoint.
    This can indicate a potential adversary adding a backdoor to establish persistence or escalate privileges.
references:
    - https://github.com/RhinoSecurityLabs/pacu/blob/866376cd711666c775bbfcde0524c817f2c5b181/pacu/modules/ecs__backdoor_task_def/main.py
    - https://docs.aws.amazon.com/AmazonECS/latest/APIReference/API_RegisterTaskDefinition.html
    - https://docs.aws.amazon.com/AmazonECS/latest/developerguide/task-iam-roles.html
author: Darin Smith
date: 2022-06-07
modified: 2023-04-24
tags:
    - attack.persistence
    - attack.t1525
logsource:
    product: aws
    service: cloudtrail
detection:
    selection:
        eventSource: 'ecs.amazonaws.com'
        eventName:
            - 'DescribeTaskDefinition'
            - 'RegisterTaskDefinition'
            - 'RunTask'
        requestParameters.containerDefinitions.command|contains: '$AWS_CONTAINER_CREDENTIALS_RELATIVE_URI'
    condition: selection
falsepositives:
    - Task Definition being modified to request credentials from the Task Metadata Service for valid reasons
level: medium

Original YAML and metadata in JSON

False positives

• Task Definition being modified to request credentials from the Task Metadata Service for valid reasons

Source references

• https://github.com/RhinoSecurityLabs/pacu/blob/866376cd711666c775bbfcde0524c817f2c5b181/pacu/modules/ecs__backdoor_task_def/main.py
• https://docs.aws.amazon.com/AmazonECS/latest/APIReference/API_RegisterTaskDefinition.html
• https://docs.aws.amazon.com/AmazonECS/latest/developerguide/task-iam-roles.html