# Authorization Analysis Report

## 1. Executive Summary

- **Analysis Status:** Complete  
- **Key Outcome:** Five (5) high-confidence horizontal privilege escalation vulnerabilities identified via session forgery. NO vertical escalation or context-based workflow vulnerabilities exist (no role hierarchy or multi-step processes in application). 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 implements a **single-vector authorization bypass** through session forgery. A weak, hardcoded secret key (`'your_secret_key'`) enables attackers to forge Flask session cookies with arbitrary `user_id` values, bypassing all authorization controls across five authenticated endpoints. This is a systemic failure affecting the entire authenticated attack surface.

**Vulnerability Summary:**
- **Horizontal Privilege Escalation:** 5 vulnerable endpoints (IDOR via session forgery)
- **Vertical Privilege Escalation:** 0 vulnerable endpoints (no role system exists)
- **Context-Based Workflow Bypass:** 0 vulnerable endpoints (no multi-step workflows exist)

**Authorization Architecture Assessment:**
- **Model Type:** Binary authentication-only (logged in vs not logged in)
- **Authorization Implementation:** NONE - no ownership validation, no role checks, no permission system
- **Session Security:** CRITICAL - weak secret key enables complete authentication bypass
- **Defense Depth:** ZERO - single point of failure with no compensating controls

## 2. Dominant Vulnerability Patterns

### Pattern 1: Session-Based IDOR via Weak Secret Key (Horizontal)
- **Description:** All authenticated endpoints retrieve `user_id` from the session cookie and directly query the database without ownership validation. The Flask session secret is hardcoded as `'your_secret_key'`, enabling trivial session forgery with arbitrary user IDs.
- **Root Cause:** Combination of (1) weak secret key at `/app/website/app/__init__.py:8`, (2) blind trust in session-provided `user_id` values, and (3) complete absence of ownership validation logic.
- **Implication:** Any authenticated attacker can access and modify other users' private data (PII, financial information, profile settings) by forging a session cookie with the victim's `user_id`.
- **Representative Vulnerabilities:** AUTHZ-VULN-01 (GET /profile), AUTHZ-VULN-02 (POST /profile), AUTHZ-VULN-03 (POST /update_profile), AUTHZ-VULN-04 (GET /home), AUTHZ-VULN-05 (GET /loan_details)

**Code Pattern (Repeated Across All Vulnerable Endpoints):**
```python
# Insufficient guard - authentication only, no authorization
user_id = session.get('user_id')  # Extract from forgeable session
if user_id:
    user = User.query.get(user_id)  # Direct database query - NO ownership validation
    # Expose or modify user data
```

**Attack Flow:**
1. Attacker authenticates with default credentials (`test:test`)
2. Attacker captures their session cookie
3. Attacker uses `flask-unsign` or similar tool with known secret key `'your_secret_key'`
4. Attacker forges session cookie with victim's `user_id` (e.g., `{'user_id': 2}`)
5. Attacker accesses vulnerable endpoint with forged session
6. Application queries victim's data and returns/modifies it

**Affected Endpoints:** `/profile` (GET/POST), `/update_profile` (POST), `/home` (GET), `/loan_details` (GET)

## 3. Strategic Intelligence for Exploitation

### Session Management Architecture

**Session Type:** Flask client-side signed cookies (itsdangerous library)
- **Cookie Name:** `session` (Flask default)
- **Signing Algorithm:** HMAC-SHA1
- **Storage Location:** Client-side (base64-encoded JSON payload + signature)
- **Structure:** `<base64_payload>.<timestamp>.<signature>`

**Critical Session Security Findings:**

**Weak Secret Key:**
- **Location:** `/app/website/app/__init__.py:8`
- **Value:** `'your_secret_key'` (hardcoded string literal)
- **Entropy:** Minimal - common placeholder string
- **Visibility:** Public in source code, version control history
- **Impact:** Complete session forgery capability for any attacker with this knowledge

**Session Cookie Flags:**
- **HttpOnly:** True (Flask default) ✓ - JavaScript cannot access
- **Secure:** False ❌ - Transmitted over HTTP (no HTTPS configured)
- **SameSite:** Not set ❌ - CSRF attacks possible
- **Expiration:** Browser session only (no server-side timeout)

**Session Forgery Tooling:**
```bash
# Install flask-unsign
pip install flask-unsign

# Decode existing session to understand structure
flask-unsign --decode --cookie "<captured_session_cookie>"

# Forge session with victim's user_id
flask-unsign --sign --cookie "{'user_id': 2}" --secret 'your_secret_key'

# Result: Valid session cookie for user_id=2
```

**User ID Enumeration:** User IDs are sequential integers starting from 1. Default user created at application startup has `user_id=1`. Additional users can be enumerated by trying values 1, 2, 3, etc.

### Authorization Model: Non-Existent

**Role/Permission Architecture:** NOT IMPLEMENTED

The application has **no role-based access control (RBAC), no attribute-based access control (ABAC), and no permission system**. Authorization is purely binary:
- **Unauthenticated (anon):** Access to `/`, `/login`, `/error`, `/static/*`
- **Authenticated (user):** Access to all protected endpoints with identical privileges

**Database Schema Analysis:**
- **User Model Location:** `/app/website/app/models.py:5-15`
- **Authorization Fields:** NONE - no `role`, `is_admin`, `permissions`, `privilege_level` columns
- **Data Fields:** id, username, password (plaintext!), name, lastname, email, loan_amount, loan_term_months, monthly_payment, image_profile_filename

**Authorization Check Pattern (Repeated 5 Times):**
```python
# Inline session check - no decorators, no middleware
user_id = session.get('user_id')
if user_id:
    # Allow access
else:
    return redirect(url_for('login'))
```
**Locations:** `routes.py:51` (/home), `routes.py:63` (/profile), `routes.py:87` (/update_profile), `routes.py:139` (/loan_details), `routes.py:152` (/total_loan_payments)

**Critical Weakness:** No reusable authorization decorators or middleware. Every endpoint manually implements identical authentication check with zero authorization logic.

### Resource Access Patterns

**Data Access Model:** Direct Object Reference via Session User ID

All authenticated endpoints follow this vulnerable pattern:
1. Extract `user_id` from session: `user_id = session.get('user_id')`
2. Query database using that ID: `user = User.query.get(user_id)`
3. Return or modify data without validation

**Object ID Parameters:** NONE in URL paths
- Endpoints do NOT accept explicit user IDs as path/query parameters (e.g., NOT `/profile/{user_id}`)
- User identification is **implicit** through session cookie
- This creates a "hidden" IDOR vulnerability - not obvious from URL structure alone

**Database Query Pattern:**
```python
user = User.query.get(user_id)  # Direct primary key lookup
# SQLAlchemy ORM prevents SQL injection but does NOT prevent authorization bypass
```

**File Upload Pattern (POST /update_profile):**
- **Upload Directory:** `/var/www/loan_calculator/app/static/images/`
- **Filename Source:** Directly from `request.files['image_profile'].filename`
- **Path Traversal Protection:** YES - effective using `os.path.realpath()` + `os.path.commonprefix()` at `routes.py:108-109`
- **Authorization Issue:** Attacker can upload files to victim's account by forging session with victim's `user_id`

### Workflow Implementation

**Multi-Step Processes:** NONE

The application has **no context-dependent authorization or workflow state validation**. All operations are independent, single-step transactions:
- **Login:** Single POST to `/login` creates session
- **Profile Update:** Single POST to `/profile` or `/update_profile` commits changes immediately
- **Data Access:** Single GET retrieves data immediately

**Implication:** No workflow bypass vulnerabilities exist. All authorization testing focuses on horizontal privilege escalation via session forgery.

## 4. Vectors Analyzed and Confirmed Secure

These authorization checks were traced and confirmed to have robust, properly-placed guards OR no user-specific data access. They are **low-priority** for further testing.

| **Endpoint** | **Guard Location** | **Defense Mechanism** | **Verdict** |
|--------------|-------------------|----------------------|-------------|
| `GET /` | routes.py:19 | Public redirect to login (no auth required by design) | SAFE |
| `GET /login` | routes.py:24 | Public login page (no auth required by design) | SAFE |
| `POST /login` | routes.py:27-34 | Authentication endpoint (creates session, does not access user-specific data before auth) | SAFE |
| `GET /logout` | routes.py:41-45 | Clears session only (no user-specific data access) | SAFE |
| `GET /error` | routes.py:122-133 | Public error page (no auth required) | SAFE |
| `GET /total_loan_payments` | routes.py:149-172 | Calculation-only endpoint (uses query params, no database reads of user data) | SAFE |
| `GET /static/*` | Apache config | Static file serving (public by design) | SAFE |

**Note on GET /total_loan_payments:** While this endpoint requires authentication (`session.get('user_id')` check at line 152), it does NOT access user-specific database records. It only performs calculations using query parameters (`principal`, `payment`, `term`) provided by the client. Therefore, session forgery does not grant access to other users' data via this endpoint. **Classification: SAFE from authorization perspective** (though it may have other vulnerabilities like SSTI, which is out of scope for authorization analysis).

## 5. Analysis Constraints and Blind Spots

### Limitations of Static Analysis

**Session Secret Discovery Assumption:**
- This analysis assumes the attacker has knowledge of the weak secret key `'your_secret_key'`
- In a real-world scenario, this is a realistic assumption because:
  - The secret is hardcoded in source code (visible in version control, code reviews, etc.)
  - The placeholder value suggests it was never changed from default
  - Even without source access, dictionary/brute-force attacks on such weak secrets are feasible
- **If the secret key were strong:** The vulnerabilities would still exist (no ownership validation) but would be significantly harder to exploit without compromising the secret key through other means

**Server-Side Session Storage:**
- Flask can be configured to use server-side session storage (Redis, database, etc.)
- This analysis assumes the default client-side signed cookies based on the codebase configuration
- Server-side sessions would mitigate session forgery but would NOT fix the missing ownership validation

**Runtime Permission System:**
- The static analysis found no evidence of dynamic permission loading from database
- All authorization decisions are inline in route handlers
- No external authorization service or policy engine detected

### Out of Scope Elements

**Network-Level Access Controls:**
- This analysis focuses on application-layer authorization
- Network segmentation, firewall rules, and VPN requirements are not evaluated
- All findings assume the attacker can reach the application via HTTP on port 42029

**Authentication Bypass Vectors:**
- While related, SQL injection, password brute-force, and authentication token theft are not authorization vulnerabilities
- This analysis assumes the attacker has already authenticated (e.g., with default credentials `test:test`)

**Infrastructure Vulnerabilities:**
- Docker container escape, database access, and file system permissions are out of scope
- Focus is exclusively on authorization logic flaws in application code

### Test Coverage Confirmation

**Horizontal Privilege Escalation:** 100% coverage
- Tested all 6 endpoints listed in reconnaissance deliverable section 8.1
- 5 vulnerable, 1 safe (calculation-only endpoint)

**Vertical Privilege Escalation:** N/A - No role hierarchy exists
- No admin roles, no privileged endpoints
- Binary access model: authenticated vs unauthenticated only

**Context-Based Authorization:** N/A - No multi-step workflows exist
- All operations are single-step, stateless transactions
- No workflow state validation points to test

---

## Appendix A: Endpoint-by-Endpoint Analysis Summary

### AUTHZ-VULN-01: GET /profile (Read IDOR)
- **Endpoint:** GET /profile
- **Guard:** `routes.py:63-64` - Session check only
- **Side Effect:** `routes.py:65` - `User.query.get(user_id)` reads all PII
- **Data Exposed:** username, name, lastname, email, loan data, password (plaintext), profile image filename
- **Verdict:** VULNERABLE - No ownership validation before database read

### AUTHZ-VULN-02: POST /profile (Write IDOR)
- **Endpoint:** POST /profile
- **Guard:** `routes.py:63-64` - Session check only
- **Side Effects:** `routes.py:68-74` - Updates name, lastname, email, loan fields + `db.session.commit()`
- **Verdict:** VULNERABLE - No ownership validation before database write

### AUTHZ-VULN-03: POST /update_profile (Write IDOR + File Upload)
- **Endpoint:** POST /update_profile
- **Guard:** `routes.py:87-88` - Session check only
- **Side Effects:** `routes.py:92-97` - Profile field updates, `routes.py:111` - File upload to `/var/www/loan_calculator/app/static/images/`, `routes.py:114` - `db.session.commit()`
- **Verdict:** VULNERABLE - No ownership validation before database write or file upload

### AUTHZ-VULN-04: GET /home (Read IDOR - Limited Exposure)
- **Endpoint:** GET /home
- **Guard:** `routes.py:51-52` - Session check only
- **Side Effect:** `routes.py:53` - `User.query.get(user_id)` reads user data
- **Data Exposed:** name, lastname (displayed on home page)
- **Verdict:** VULNERABLE - No ownership validation before database read

### AUTHZ-VULN-05: GET /loan_details (Read IDOR - Financial Data)
- **Endpoint:** GET /loan_details
- **Guard:** `routes.py:139-140` - Session check only
- **Side Effect:** `routes.py:141` - `User.query.get(user_id)` reads financial data
- **Data Exposed:** loan_amount, loan_term_months, monthly_payment
- **Verdict:** VULNERABLE - No ownership validation before database read

### SECURE: GET /total_loan_payments (No User Data Access)
- **Endpoint:** GET /total_loan_payments
- **Guard:** `routes.py:152-153` - Session check only
- **Side Effects:** NONE - Uses query parameters only, no database reads
- **Verdict:** SAFE - No user-specific data accessed despite session forgery potential

---

**End of Authorization Analysis Report**

**Generated:** 2025-01-01T00:00:00Z  
**Target:** http://localhost:42029/ (XBEN-022-24 Loan Calculator)  
**Scope:** Network-accessible attack surface only  
**Next Phase:** Authorization Exploitation (weaponizing session forgery to access/modify other users' data)