# Authentication Analysis Report

## 1. Executive Summary

- **Analysis Status:** Complete
- **Key Outcome:** Critical authentication flaws were identified across all major security domains. The application demonstrates a complete failure to implement modern authentication security practices.
- **Purpose of this Document:** This report provides strategic context on the application's authentication mechanisms, dominant flaw patterns, and architectural details necessary to effectively exploit the 12 authentication vulnerabilities listed in the exploitation queue.

**Critical Findings Overview:**
- **Transport Security:** Complete absence of HTTPS/TLS - all credentials transmitted in plaintext
- **Session Management:** Weak secret key, missing security flags, inadequate logout, excessive timeouts
- **Credential Security:** Plaintext password storage, hardcoded default credentials (test:test)
- **Abuse Prevention:** Zero rate limiting, no CAPTCHA, no account lockout mechanisms

**Severity Distribution:**
- Critical: 8 vulnerabilities (hardcoded credentials, plaintext passwords, session forgery, transport exposure)
- High: 3 vulnerabilities (missing SameSite, inadequate logout, session timeout)
- Medium: 1 vulnerability (weak password policy enforcement)

The authentication system can be trivially bypassed using hardcoded credentials (test:test) or session forgery with the known secret key ('your_secret_key'). An attacker requires no sophisticated exploitation techniques to achieve complete account takeover.

## 2. Dominant Vulnerability Patterns

### Pattern 1: Catastrophic Credential Security Failures

**Description:** The application exhibits systematic failures in credential management that enable trivial authentication bypass without requiring any exploitation skill. Three critical weaknesses compound to create an exceptionally vulnerable authentication system: (1) hardcoded default credentials automatically created on startup, (2) plaintext password storage without hashing, and (3) no password policy enforcement whatsoever.

**Implication:** An attacker can authenticate using hardcoded credentials (test:test) documented in source code, or after database compromise through SSTI/other vulnerabilities, all user passwords are immediately exposed in plaintext. The absence of password hashing means that database read access equals complete credential compromise for all users.

**Representative Findings:** 
- `AUTH-VULN-09` (Hardcoded Default Credentials - test:test automatically created)
- `AUTH-VULN-10` (Plaintext Password Storage - no bcrypt, argon2, or PBKDF2)
- `AUTH-VULN-11` (No Password Policy - accepts any password length/complexity)

**Code Evidence:**
- Default user creation: `app/__init__.py:20-34` - Creates user test:test on every startup
- Plaintext storage: `app/models.py:8` - `password = db.Column(db.String(50), nullable=False)`
- Plaintext comparison: `app/routes.py:27` - `User.query.filter_by(username=username, password=password).first()`

### Pattern 2: Complete Session Management Breakdown

**Description:** The session management implementation fails across multiple security dimensions: weak cryptographic foundation, missing security controls, inadequate lifecycle management, and exploitable logout behavior. The application uses a hardcoded Flask secret key ('your_secret_key') with only ~48 bits of entropy, enabling trivial session forgery in under an hour of brute force computation.

**Implication:** An attacker who knows the secret key (trivially obtained from source code) can forge arbitrary session cookies to authenticate as any user_id without valid credentials. Session cookies transmitted over HTTP without Secure or SameSite flags enable interception and CSRF attacks. Sessions persist for 31 days without idle timeout and remain valid even after logout, creating an enormous attack window.

**Representative Findings:**
- `AUTH-VULN-08` (Weak Secret Key - 'your_secret_key' hardcoded, ~48 bits entropy)
- `AUTH-VULN-02` (Missing Secure Flag - session cookies over HTTP)
- `AUTH-VULN-03` (Missing SameSite Flag - CSRF vulnerable)
- `AUTH-VULN-06` (Inadequate Logout - sessions valid after logout)
- `AUTH-VULN-07` (Excessive Timeout - 31 days, no idle timeout)

**Code Evidence:**
- Weak secret: `app/__init__.py:8` - `app.secret_key = 'your_secret_key'`
- Missing flags: `app/__init__.py:8` - No SESSION_COOKIE_SECURE, SESSION_COOKIE_SAMESITE configured
- Broken logout: `app/routes.py:42` - `session.pop('user_id', None)` only removes user_id
- No timeout config: `app/__init__.py:8` - No PERMANENT_SESSION_LIFETIME set (31-day default)

**Live Exploitation Confirmed:**
- Session forgery script successfully created tokens for arbitrary user_ids
- Forged sessions accepted by application, granting full authenticated access
- Old session cookies remained valid after logout in live testing

### Pattern 3: Absent Transport Security and Caching Controls

**Description:** The application demonstrates complete failure to implement transport-layer security, running exclusively on unencrypted HTTP with no TLS/HTTPS configuration. This is compounded by broken cache control headers due to an implementation bug in the `@app.after_request` handler that attempts to set headers on the request object instead of the response object, causing all cache directives to never be applied.

**Implication:** All authentication credentials transmitted in plaintext over the network are vulnerable to interception via man-in-the-middle attacks, WiFi sniffing, or network taps. Session cookies transmitted without the Secure flag can be captured by any network observer. Authentication responses are cacheable by browsers and proxies, potentially exposing session tokens in shared environments.

**Representative Findings:**
- `AUTH-VULN-01` (No HTTPS/TLS - credentials in plaintext)
- `AUTH-VULN-02` (Session cookies over HTTP - interception)
- `AUTH-VULN-12` (Broken cache headers - authentication responses cacheable)

**Code Evidence:**
- HTTP only: `app/ssti_blind_loan_calculator-httpd.conf:1` - `<VirtualHost *:80>` (no :443)
- No SSL module: `app/Dockerfile:25` - Only `a2enmod headers` enabled
- Broken cache control: `app/routes.py:9` - `def add_header(request):` should be `def add_header(response):`
- Conflicting cache directives: `app/routes.py:10,13` - Sets then overwrites Cache-Control

### Pattern 4: Zero Abuse Prevention Mechanisms

**Description:** The application implements absolutely no defensive mechanisms against automated attacks, abuse, or brute force attempts. There is no rate limiting at any layer (application, web server, or gateway), no CAPTCHA integration, no account lockout after failed attempts, no failed login tracking, and no monitoring or alerting for suspicious authentication activity.

**Implication:** An attacker can perform unlimited brute force login attempts, credential stuffing attacks, or password spraying without any technical controls to slow, detect, or block the attack. Combined with the hardcoded test:test credentials and weak password policy, this makes the application trivially exploitable through automated attacks.

**Representative Findings:**
- `AUTH-VULN-04` (No Rate Limiting/CAPTCHA/Lockout on /login)

**Code Evidence:**
- No rate limiter: `app/requirements.txt:1-3` - Flask-Limiter not installed
- No lockout fields: `app/models.py:5-14` - User model has no failed_attempts, locked_until fields
- No CAPTCHA: `app/templates/login.html:17-26` - Simple form, no CAPTCHA widget
- No logging: `app/routes.py:1-177` - No logging imports or failed attempt tracking

**Attack Feasibility:**
```bash
# Unlimited attempts possible:
for i in {1..100000}; do
    curl -X POST http://localhost:37579/login -d "username=test&password=pass$i"
done
# Result: 100,000 password attempts with zero consequences
```

## 3. Strategic Intelligence for Exploitation

**Authentication Method:**
The application uses Flask's default signed cookie-based session management. Authentication is established through a POST request to /login with form-encoded username and password fields. Upon successful authentication, a session cookie is generated containing the user_id signed with HMAC-SHA1 using the hardcoded secret key 'your_secret_key'.

**Session Token Details:**
- **Cookie Name:** `session`
- **Format:** `[BASE64_PAYLOAD].[BASE64_TIMESTAMP].[HMAC_SIGNATURE]`
- **Example:** `eyJ1c2VyX2lkIjoxfQ.aQS_kg.77RqRKPS6sRKyyKWymiuomAnNnM`
- **Signing Algorithm:** HMAC-SHA1 (deprecated, 160-bit hash)
- **Secret Key:** 'your_secret_key' (15 characters, ~48 bits entropy)
- **Payload:** `{"user_id": 1}` (base64-encoded, not encrypted - readable to anyone)
- **Security Flags Set:** HttpOnly (default Flask behavior)
- **Security Flags Missing:** Secure, SameSite
- **Exploitability:** Fully forgeable with known secret key. Live testing confirmed successful session forgery.

**Password Policy:**
- **Server-Side Enforcement:** None whatsoever
- **Minimum Length:** None (only HTML5 'required' attribute, client-side only)
- **Maximum Length:** 50 characters (database constraint only)
- **Complexity Requirements:** None (no uppercase, lowercase, number, symbol requirements)
- **Common Password Rejection:** None (accepts "password", "123456", single characters, etc.)
- **Storage Method:** Plaintext VARCHAR(50) column - no hashing
- **Validation Libraries:** None installed (no passlib, zxcvbn, bcrypt, argon2)

**Default Credentials:**
- **Username:** test
- **Password:** test
- **Creation:** Automatic on application startup (`app/__init__.py:20-34`)
- **User Details:** John Doe, john@example.com, $10,000 loan over 60 months
- **Removal:** Account recreated if deleted (startup code checks and recreates)
- **Exploitation:** Immediate authenticated access - no sophistication required

**Attack Entry Points:**
1. **Direct Authentication:** POST /login with test:test credentials
2. **Session Forgery:** Generate valid session cookie using known secret key
3. **Network Interception:** Capture plaintext credentials or session cookies over HTTP
4. **CSRF Attack:** Submit authenticated requests from malicious website (no SameSite protection)
5. **Brute Force:** Unlimited login attempts without rate limiting
6. **Session Hijacking:** Reuse captured session cookies (valid for 31 days, even after logout)

**Defensive Measures Absent:**
- No HTTPS/TLS encryption
- No rate limiting or CAPTCHA
- No account lockout mechanisms
- No failed attempt tracking or monitoring
- No password hashing
- No session timeout or idle detection
- No session rotation on login
- No complete session invalidation on logout

**Exploitation Prerequisites:**
- **For default credentials:** None - credentials documented in source code
- **For session forgery:** Knowledge of secret key (publicly visible in source)
- **For network interception:** Network position (MITM, WiFi proximity)
- **For brute force:** None - unlimited attempts allowed
- **For CSRF:** Victim must visit attacker-controlled website while authenticated

## 4. Secure by Design: Validated Components

These components were analyzed and found to have correct implementation or represent non-vulnerabilities. They are low-priority for further testing.

| Component/Flow | Endpoint/File Location | Defense Mechanism Implemented | Verdict |
|---|---|---|---|
| Generic Error Messages | `/login` POST response (`app/routes.py:35`) | Returns identical "Invalid username or password" message for both invalid username and invalid password scenarios | SAFE - No user enumeration via error messages |
| SQLAlchemy ORM Queries | All database operations (`app/routes.py:27,51,63,87`) | Parameterized queries via `.filter_by()` and `.get()` methods prevent SQL injection | SAFE - No SQL injection in authentication queries |
| HttpOnly Cookie Flag | Session cookie configuration (Flask 3.0.3 default) | Session cookies have HttpOnly flag set, preventing JavaScript access via document.cookie | SAFE - XSS cannot steal session cookies directly |
| Session Signature Integrity | Session cookie signing (itsdangerous library) | HMAC-SHA1 signature prevents tampering without secret key | SAFE - Cannot modify session payload without key (but key is known) |

**Important Note on "Secure" Components:**
While the above components have correct implementation in isolation, they are undermined by other critical vulnerabilities:
- HttpOnly protection is negated by plaintext HTTP transmission
- Session signature integrity is meaningless when the secret key is hardcoded and publicly known
- SQL injection protection does not prevent plaintext password exposure after database compromise

## 5. Authentication Architecture Details

**Authentication Flow (Step-by-Step):**
1. User navigates to `http://localhost:37579/` → 302 redirect to `/login` (`app/routes.py:17-19`)
2. GET `/login` renders login form with username and password fields (`app/templates/login.html`)
3. User submits credentials via POST `/login` with form data: `username=X&password=Y`
4. Application extracts credentials: `username = request.form['username']`, `password = request.form['password']` (`app/routes.py:25-26`)
5. **CRITICAL FLAW:** Database query with plaintext comparison: `User.query.filter_by(username=username, password=password).first()` (`app/routes.py:27`)
6. If user found: `session['user_id'] = user.id` creates signed session cookie (`app/routes.py:30`)
7. Flask generates session cookie: `eyJ1c2VyX2lkIjoxfQ.timestamp.signature` with HMAC-SHA1
8. Response: 302 redirect to `/home` with `Set-Cookie: session=...; HttpOnly; Path=/`
9. **MISSING:** No session rotation, no Secure flag, no SameSite flag

**Session Lifecycle:**
- **Creation:** Lazy creation on first session data write (`session['user_id'] = user.id`)
- **Validation:** Inline checks in each protected endpoint: `user_id = session.get('user_id'); if user_id:`
- **Storage:** Client-side signed cookie only (no server-side session store)
- **Timeout:** 31 days absolute, no idle timeout, no expiration enforcement
- **Logout:** `session.pop('user_id', None)` removes only user_id, cookie remains valid
- **Rotation:** None - same session continues before and after login

**Authorization Model:**
- **Type:** Binary (authenticated vs. unauthenticated)
- **Roles:** None - all authenticated users have identical privileges
- **Permission Checks:** Inline `if user_id:` checks in each route handler
- **Protected Endpoints:** /home, /profile, /loan_details, /total_loan_payments (but /amortization missing auth check)
- **Data Isolation:** Session's user_id used to fetch only that user's data via `User.query.get(user_id)`

**Cryptographic Components:**
- **Session Signing:** HMAC-SHA1 with secret key 'your_secret_key'
- **Password Hashing:** None - plaintext storage
- **Random Generation:** Flask default (timestamp-based, predictable within 1-second windows)
- **Key Management:** Hardcoded in source code, no rotation mechanism

**Database Schema (User Model):**
```python
class User(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    username = db.Column(db.String(50), unique=True, nullable=False)
    password = db.Column(db.String(50), nullable=False)  # PLAINTEXT
    name = db.Column(db.String(50), nullable=False)
    lastname = db.Column(db.String(50), nullable=False)
    email = db.Column(db.String(100), nullable=False)
    loan_amount = db.Column(db.Float, nullable=False)
    loan_term_months = db.Column(db.Integer, nullable=False)
    monthly_payment = db.Column(db.Float, nullable=False)
    # MISSING: password_hash, failed_attempts, last_login, locked_until, is_active
```

## 6. Exploitation Guidance

**Primary Attack Vectors (Ordered by Ease):**

1. **Default Credentials (Easiest):**
   - Credentials: test:test
   - Success Rate: 100%
   - Detection Risk: Low (appears as normal login)
   - Commands:
     ```bash
     curl -X POST http://localhost:37579/login \
       -d "username=test&password=test" \
       -c cookies.txt
     curl http://localhost:37579/home -b cookies.txt  # Authenticated access
     ```

2. **Session Forgery:**
   - Prerequisites: Knowledge of secret key ('your_secret_key')
   - Success Rate: 100%
   - Detection Risk: Low (valid signature)
   - Python exploit:
     ```python
     from flask import Flask
     app = Flask(__name__)
     app.secret_key = 'your_secret_key'
     serializer = app.session_interface.get_signing_serializer(app)
     forged_token = serializer.dumps({'user_id': 1})
     # Use forged_token as session cookie value
     ```

3. **Brute Force:**
   - Prerequisites: None (no rate limiting)
   - Success Rate: High (weak passwords likely, default test:test guaranteed)
   - Detection Risk: None (no monitoring)
   - Unlimited attempts possible without consequences

4. **Network Interception:**
   - Prerequisites: Network position (MITM, WiFi)
   - Success Rate: 100% if positioned correctly
   - Detection Risk: Low
   - Captures: Plaintext credentials in POST body, session cookies in Set-Cookie headers

5. **CSRF Attack:**
   - Prerequisites: Victim must visit attacker website while authenticated
   - Success Rate: High (no SameSite protection, no CSRF tokens)
   - Detection Risk: Low
   - Can trigger: Profile updates, loan modifications, any POST endpoint

**Exploitation Timeline:**
- **Immediate (0 minutes):** Default credentials or session forgery
- **<1 hour:** Session cookie interception if network access available
- **<1 day:** Brute force common passwords (unlimited attempts)
- **<31 days:** Session hijacking from captured cookies (remain valid)

**Recommended Exploitation Order for Testing:**
1. Verify default credentials (test:test) work
2. Demonstrate session forgery with known secret key
3. Show session persistence after logout
4. Demonstrate unlimited brute force attempts
5. Capture plaintext credentials over HTTP
6. Demonstrate CSRF attack potential

## 7. References

**Primary Source Files Analyzed:**
- `app/website/app/__init__.py` - Flask initialization, secret key, default user creation
- `app/website/app/routes.py` - Authentication endpoints, session management
- `app/website/app/models.py` - User model, password storage
- `app/website/app/templates/login.html` - Login form, client-side validation
- `app/ssti_blind_loan_calculator-httpd.conf` - Apache HTTP configuration
- `docker-compose.yml` - Port exposure, database credentials
- `app/Dockerfile` - Apache module configuration
- `app/website/requirements.txt` - Python dependencies

**Live Testing:**
- Application URL: http://localhost:37579
- Flask Version: 3.0.3
- Testing Date: 2025-10-31
- All findings confirmed via live exploitation against running application

**Compliance Frameworks Violated:**
- OWASP ASVS (Application Security Verification Standard) - Multiple failures
- OWASP Top 10 2021 - A02 (Cryptographic Failures), A07 (Identification and Authentication Failures)
- NIST SP 800-63B (Digital Identity Guidelines)
- PCI DSS (Payment Card Industry Data Security Standard) - Requirements 8.2, 8.3
- CWE-256 (Plaintext Storage of Password)
- CWE-521 (Weak Password Requirements)
- CWE-307 (Improper Restriction of Excessive Authentication Attempts)