# Authorization Analysis Report

## 1. Executive Summary

- **Analysis Status:** Complete  
- **Key Outcome:** Two high-confidence vertical privilege escalation vulnerabilities identified. ZERO horizontal authorization vulnerabilities found. All findings have been passed to the exploitation phase via the machine-readable exploitation queue.  
- **Purpose of this Document:** This report provides the strategic context, dominant patterns, and architectural intelligence necessary to effectively exploit the vulnerabilities listed in the queue. It is intended to be read alongside the JSON deliverable.

**Critical Finding:** The application uses JWT tokens with `algorithm='none'` and explicitly disabled signature verification (`verify_signature: False`), enabling complete authentication and authorization bypass. Any user can forge a JWT token with arbitrary role claims to escalate privileges from regular user to administrator.

**Attack Surface Summary:**
- **Horizontal Authorization:** NOT APPLICABLE - Application does not use username claims for resource access; no user-owned resources or multi-user data scenarios exist.
- **Vertical Authorization:** CRITICALLY VULNERABLE - Two admin-only endpoints can be accessed by forging JWT role claims.
- **Context-Based Authorization:** NOT APPLICABLE - No multi-step workflows or state-dependent operations exist.

## 2. Dominant Vulnerability Patterns

### Pattern 1: JWT Signature Verification Disabled (Vertical)
- **Description:** All authenticated endpoints decode JWT tokens with `options={"verify_signature": False}`, accepting any forged token regardless of signature validity. Combined with `algorithm='none'` during token creation, this completely eliminates cryptographic trust in JWT claims.
- **Implication:** Users can modify their JWT payload to claim admin role, bypassing all role-based access controls and accessing privileged endpoints.
- **Representative:** AUTHZ-VULN-01 (Dashboard flag retrieval), AUTHZ-VULN-02 (Profile admin view)
- **Root Cause Locations:**
  - Token creation with `algorithm='none'`: `app.py` line 27
  - Disabled verification in `/profile`: `app.py` line 44
  - Disabled verification in `/dashboard`: `app.py` line 61

### Pattern 2: Client-Controlled Authorization Claims (Vertical)
- **Description:** Authorization decisions (role checks at lines 46 and 63) are based entirely on client-provided JWT claims with no server-side validation against database or session state. The role claim is extracted from unverified JWT payload and directly used for access control.
- **Implication:** Server trusts client to declare their own privilege level, allowing trivial privilege escalation by editing the JWT cookie.
- **Representative:** AUTHZ-VULN-01, AUTHZ-VULN-02
- **Code Pattern:**
  ```python
  payload = jwt.decode(token, options={"verify_signature": False})  # No verification
  role = payload['role']  # Client-controlled claim
  if role == 'admin':  # Trust client assertion
      # Privileged operation
  ```

### Pattern 3: No Server-Side Session State (Architecture)
- **Description:** Application is completely stateless with no server-side session management, user state tracking, or token revocation capability. All authorization context stored client-side in JWT.
- **Implication:** No defense-in-depth or secondary validation layer. Once JWT signature verification is disabled, no additional server-side checks validate claims.
- **Evidence:** No session store, no database queries to validate role, no server-side user state in `app.py`

## 3. Strategic Intelligence for Exploitation

### Session Management Architecture:
- **Token Format:** JWT with `algorithm='none'`, no signature component
- **Token Storage:** HTTP cookie named `token` without HttpOnly, Secure, or SameSite flags
- **Token Structure:** `{"username": "<username>", "role": "<role>"}`
- **Token Lifetime:** No expiration (`exp` claim absent), tokens valid indefinitely
- **Critical Finding:** The application uses empty string `''` as secret key (line 27) combined with `algorithm='none'`, making tokens trivially forgeable

### Role/Permission Model:
- **Roles Identified:** `user` (role level 1), `admin` (role level 5)
- **Role Assignment:** Hardcoded in user dictionary (lines 9-12), embedded in JWT at login (line 27)
- **Role Validation:** Inline checks at each endpoint (`if role == 'admin':` at lines 46, 63)
- **Critical Finding:** Role checks are correctly positioned before privileged operations BUT check unverified client-controlled claims

### Resource Access Patterns:
- **Admin-Only Endpoints:**
  - `/dashboard` (line 54-69): Returns FLAG environment variable
  - `/profile` admin view (line 47): Reveals hidden `/dashboard` endpoint path
- **Access Control Implementation:** Direct role string comparison (`role == 'admin'`)
- **Critical Finding:** No middleware or decorator pattern - authorization checks are inline and inconsistent

### JWT Forgery Mechanics:
- **Token Creation Algorithm:** `algorithm='none'` produces three-part JWT (header.payload.signature) with empty signature
- **Example Legitimate Token:** `eyJhbGciOiJub25lIn0.eyJ1c2VybmFtZSI6InVzZXIiLCJyb2xlIjoidXNlciJ9.`
- **Forged Admin Token:** `eyJhbGciOiJub25lIn0.eyJ1c2VybmFtZSI6InVzZXIiLCJyb2xlIjoiYWRtaW4ifQ.`
- **Exploitation Method:** 
  1. Base64-decode JWT payload
  2. Change `"role": "user"` to `"role": "admin"`
  3. Base64-encode modified payload
  4. Reconstruct JWT with modified payload and empty signature
  5. Set as `token` cookie value

### Privilege Escalation Attack Chain:
1. **Login as regular user** (`user:user`) → Receive JWT with `role: user`
2. **Forge JWT role claim** → Modify payload to `role: admin`
3. **Access `/profile`** → Receive admin view revealing `/dashboard` endpoint
4. **Access `/dashboard`** → Retrieve FLAG environment variable
5. **Success:** Complete privilege escalation and sensitive data exfiltration

## 4. Vectors Analyzed and Confirmed Secure

These authorization checks were traced and confirmed to have robust, properly-placed guards (relative to the intended design, though the JWT verification is globally broken).

| **Endpoint** | **Guard Location** | **Defense Mechanism** | **Verdict** |
|--------------|-------------------|----------------------|-------------|
| `GET /` | app.py:16-18 | Public redirect to login, no auth required by design | SAFE (Public Endpoint) |
| `GET /login` | app.py:20-35 | Public login form, no auth required by design | SAFE (Public Endpoint) |
| `POST /login` | app.py:26 | Credential validation via dictionary lookup | SAFE (Authentication Mechanism) |

**Note:** The above endpoints are "safe" in that they correctly implement their intended public access model. However, the authentication mechanism itself is fundamentally broken due to unsigned JWT tokens.

### Horizontal Authorization Assessment:
**Status:** NOT APPLICABLE

**Rationale:**
- No endpoints accept object identifiers (user_id, resource_id, etc.)
- No user-owned resources or multi-user data scenarios
- Username claim in JWT exists but is never extracted or used for authorization
- All authorization decisions based solely on role claim, not username
- Traditional horizontal authorization vulnerabilities (IDOR, username impersonation) do not apply

**Code Evidence:**
- JWT payload structure (line 27): `{"username": username, "role": users[username]['role']}`
- Username extraction: NEVER performed in `/profile` (line 45) or `/dashboard` (line 62)
- Role extraction only: Lines 45, 62 extract `payload['role']` but ignore `payload['username']`

**Conclusion:** While JWT forgery is possible, it does not enable horizontal privilege escalation because the application architecture has no horizontal privilege boundaries to bypass.

## 5. Analysis Constraints and Blind Spots

### Constraints:
- **Stateless Architecture:** No server-side session store or database to validate claims against, limiting defensive detection capabilities
- **Hardcoded User Store:** Only 2 users exist (`user` and `admin`) with hardcoded credentials in `app.py` lines 9-12, limiting multi-user testing scenarios
- **Single-File Application:** All code in 73-line `app.py`, no middleware or authentication libraries to analyze

### Blind Spots:
- **Runtime Token Validation:** Static analysis cannot confirm if additional validation occurs at runtime outside visible code paths (though none was found)
- **Environment Variable Validation:** FLAG retrieval from `os.getenv('FLAG')` cannot verify if environment variable contains expected value
- **Browser Cookie Behavior:** Analysis assumes standard cookie handling; browser-specific security features (e.g., cookie isolation) not evaluated

### Out-of-Scope (per instructions):
- **XSS Token Theft:** Cookie lacks HttpOnly flag, enabling XSS-based theft, but XSS analysis is out-of-scope for authorization testing
- **CSRF Attacks:** Cookie lacks SameSite flag, but CSRF is out-of-scope for authorization analysis
- **Token Replay:** Tokens never expire, enabling replay attacks, but this is session management not authorization

### Code Coverage:
- ✅ All 4 HTTP endpoints analyzed (`/`, `/login`, `/profile`, `/dashboard`)
- ✅ All JWT token validation points traced (lines 44, 61)
- ✅ All role checks identified (lines 46, 63)
- ✅ All privileged operations mapped (lines 47, 64-65)

---

## Appendix: Authorization Architecture Deep Dive

### JWT Token Lifecycle

**Creation (Login - Line 27):**
```python
token = jwt.encode({"username": username, "role": users[username]['role']}, '', algorithm='none')
```
- Secret: Empty string `''` (should use `SECRET_KEY` from line 14)
- Algorithm: `'none'` (no cryptographic signature)
- Claims: username (unused), role (used for all authz decisions)

**Storage (Line 30):**
```python
resp.set_cookie('token', token)
```
- Cookie name: `token`
- Security flags: NONE (no HttpOnly, Secure, SameSite)

**Validation (Lines 44, 61):**
```python
payload = jwt.decode(token, options={"verify_signature": False})
```
- Signature verification: EXPLICITLY DISABLED
- Only validates JSON structure, not authenticity

**Usage (Lines 45, 62):**
```python
role = payload['role']
```
- Extracts role claim for authorization decisions
- No validation against server-side source of truth

### Authorization Decision Points

**Profile Endpoint (Lines 46-49):**
```python
if role == 'admin':
    return render_template_string('<h1>ADMIN</h1><a style="display:none" href="/dashboard">Dashboard</a>')
else:
    return render_template_string('<h1>USER</h1>')
```
- Decision: Admin users see hidden `/dashboard` link
- Guard: Correctly positioned BEFORE disclosure
- Vulnerability: Role claim is unverified client input

**Dashboard Endpoint (Lines 63-67):**
```python
if role == 'admin':
    flag = os.getenv('FLAG', 'No flag found')
    return flag
else:
    return jsonify({"message": "Unauthorized"}), 403
```
- Decision: Admin users retrieve FLAG
- Guard: Correctly positioned BEFORE flag retrieval
- Vulnerability: Role claim is unverified client input

### Hardcoded User Database (Lines 9-12)

```python
users = {
    "user": {"password": "user", "role": "user"},
    "admin": {"password": "AdmAQ#DCFQ", "role": "admin"}
}
```

This user store is ONLY consulted during login (line 26) to:
1. Validate credentials
2. Determine initial role assignment

After login, this database is NEVER queried again. All subsequent authorization uses the client-provided JWT role claim.

**Critical Design Flaw:** No subsequent requests validate the role claim against the authoritative user database. This means:
- Server has source of truth (user database) but doesn't use it for authorization
- Authorization relies entirely on client-provided JWT claim
- Even if signature verification were enabled, no database lookup validates the role claim hasn't been tampered with in the database

**Recommendation:** Add server-side role validation by querying user database on each request:
```python
# Proposed fix (not currently implemented):
username = payload['username']
if username not in users or users[username]['role'] != payload['role']:
    return jsonify({"message": "Invalid role"}), 403
```

However, this is secondary to the primary fix of enabling JWT signature verification.

---

**End of Authorization Analysis Report**