CORS Bypass Using URL Proxy: Ethical Hacker Tip

You can use this as a way to (likely) bypass CORS restrictions:

https://corsproxy.io/?url=https://lnkd.in/eGQG8Btd

You can script it with:

!/bin/bash 
echo "Hitting $1 with corsproxy.io" 
curl -A "Mozilla/5.0" "https://corsproxy.io/?url=https://$1"

Keep in mind this is not a secure proxy, as if you hit ifconfig.me, it leaks your IP in the `X-Forwarded-For` chain.

You Should Know:

1. Understanding CORS Bypass

CORS (Cross-Origin Resource Sharing) is a security mechanism that restricts HTTP requests from one domain to another. Attackers (or pentesters) often bypass CORS to access restricted APIs.

2. Alternative CORS Bypass Methods

Using `cURL` with Custom Headers:

curl -H "Origin: https://evil.com" -H "Access-Control-Request-Method: GET" -X OPTIONS -v https://victim.com/api

Local Proxy Setup (Burp/ZAP):
Configure Burp Suite or OWASP ZAP to intercept and modify CORS headers.
Exploiting Misconfigured Access-Control-Allow-Origin:
```
curl -H "Origin: null" -I https://target.com 
```

3. Secure Proxy Alternatives

If `corsproxy.io` leaks your IP, use:

Self-Hosted Proxy (Nginx):

server { 
listen 80; 
location / { 
proxy_pass https://target.com; 
add_header 'Access-Control-Allow-Origin' ''; 
} 
}

Python Simple Proxy:
```
from flask import Flask, request, jsonify 
import requests</li>
</ul>

app = Flask(name)

@app.route('/proxy') 
def proxy(): 
url = request.args.get('url') 
response = requests.get(url) 
return jsonify(response.json())

if name == 'main': 
app.run(port=5000) 
```
4. Testing CORS Misconfigurations
- Manual Test:
```
curl -H "Origin: https://attacker.com" -I https://api.victim.com/data 
```
Check for:
```
Access-Control-Allow-Origin: https://attacker.com 
```
- Automated Scanning with CORStest:
```
git clone https://github.com/RUB-NDS/CORStest.git 
python CORStest.py -u https://target.com 
```
What Undercode Say

CORS bypass techniques are essential for penetration testers but can be dangerous if misused. Always ensure proper authorization before testing. Self-hosted proxies are safer than public ones like corsproxy.io.

Expected Output:

A working CORS bypass script with secure proxy alternatives for ethical hacking.

Prediction

As APIs become more prevalent, CORS misconfigurations will remain a common vulnerability, leading to increased exploitation if not properly secured.

Relevant URLs:
- CORS Misconfigurations Explained
- OWASP CORS Guide
References:

Reported By: Activity 7331622923536855040 – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅

Join Our Cyber World:

💬 Whatsapp | 💬 Telegram
Share this:

Listen to this Post

You can script it with:

You Should Know:

1. Understanding CORS Bypass

2. Alternative CORS Bypass Methods

3. Secure Proxy Alternatives

If `corsproxy.io` leaks your IP, use:

4. Testing CORS Misconfigurations

Check for:

What Undercode Say

Expected Output:

Prediction

Relevant URLs:

References:

Join Our Cyber World:

Share this:

Related Posts: