# AWS - ECS Enum

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## ECS

### Basic Information

Amazon **Elastic Container Services** or ECS provides a platform to **host containerized applications in the cloud**. ECS has two **deployment** methods, **EC2** instance type and a **serverless** option, **Fargate**. The service **makes running containers in the cloud very easy and pain free**.

ECS operates using the following three building blocks: **Clusters**, **Services**, and **Task Definitions**.

- **Clusters** are **groups of containers** that are running in the cloud. As previously mentioned, there are two launch types for containers, EC2 and Fargate. AWS defines the **EC2** launch type as allowing customers “to run \[their] containerized applications on a cluster of Amazon EC2 instances that \[they] **manage**”. **Fargate** is similar and is defined as “\[allowing] you to run your containerized applications **without the need to provision and manage** the backend infrastructure”.
- **Services** are created inside a cluster and responsible for **running the tasks**. Inside a service definition **you define the number of tasks to run, auto scaling, capacity provider (Fargate/EC2/External),** **networking** information such as VPC’s, subnets, and security groups.
  - There **2 types of applications**:
    - **Service**: A group of tasks handling a long-running computing work that can be stopped and restarted. For example, a web application.
    - **Task**: A standalone task that runs and terminates. For example, a batch job.
  - Among the service applications, there are **2 types of service schedulers**:
    - [**REPLICA**](https://docs.aws.amazon.com/AmazonECS/latest/developerguide/ecs_services.html): The replica scheduling strategy places and **maintains the desired number** of tasks across your cluster. If for some reason a task shut down, a new one is launched in the same or different node.
    - [**DAEMON**](https://docs.aws.amazon.com/AmazonECS/latest/developerguide/ecs_services.html): Deploys exactly one task on each active container instance that has the needed requirements. There is no need to specify a desired number of tasks, a task placement strategy, or use Service Auto Scaling policies.
- **Task Definitions** are responsible for **defining what containers will run** and the various parameters that will be configured with the containers such as **port mappings** with the host, **env variables**, Docker **entrypoint**...
  - Check **env variables for sensitive info**!

### Sensitive Data In Task Definitions

Task definitions are responsible for **configuring the actual containers that will be running in ECS**. Since task definitions define how containers will run, a plethora of information can be found within.

Pacu can enumerate ECS (list-clusters, list-container-instances, list-services, list-task-definitions), it can also dump task definitions.

### Enumeration

```bash
# Clusters info
aws ecs list-clusters
aws ecs describe-clusters --clusters <cluster>

# Container instances
## An Amazon ECS container instance is an Amazon EC2 instance that is running the Amazon ECS container agent and has been registered into an Amazon ECS cluster.
aws ecs list-container-instances --cluster <cluster>
aws ecs describe-container-instances --cluster <cluster> --container-instances <container_instance_arn>

# Services info
aws ecs list-services --cluster <cluster>
aws ecs describe-services --cluster <cluster> --services <services>
aws ecs describe-task-sets --cluster <cluster> --service <service>

# Task definitions
aws ecs list-task-definition-families
aws ecs list-task-definitions
aws ecs list-tasks --cluster <cluster>
aws ecs describe-tasks --cluster <cluster> --tasks <tasks>
## Look for env vars and secrets used from the task definition
aws ecs describe-task-definition --task-definition <TASK_NAME>:<VERSION>
```

### Unauthenticated Access

{{#ref}}
../aws-unauthenticated-enum-access/aws-ecs-unauthenticated-enum.md
{{#endref}}

### Privesc

In the following page you can check how to **abuse ECS permissions to escalate privileges**:

{{#ref}}
../aws-privilege-escalation/aws-ecs-privesc.md
{{#endref}}

### Post Exploitation

{{#ref}}
../aws-post-exploitation/aws-ecs-post-exploitation.md
{{#endref}}

### Persistence

{{#ref}}
../aws-persistence/aws-ecs-persistence.md
{{#endref}}

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