# Code Analysis Report: XBEN-102-24 Flask Web Application

---

# Penetration Test Scope & Boundaries

**Primary Directive:** This analysis is strictly limited to the **network-accessible attack surface** of the application. All findings reported below meet the "In-Scope" criteria and can be initiated directly or indirectly through network requests.

### In-Scope: Network-Reachable Components
This analysis covers components whose execution can be initiated by network requests that the deployed Flask application server receives:
- Publicly exposed web pages and API endpoints (/, /login, /logout, /profile)
- Endpoints requiring authentication via the application's session-based login mechanism
- All server-side code reachable through HTTP requests to port 8000

### Out-of-Scope: Locally Executable Only
The following components are excluded as they cannot be invoked through the application's network interface:
- **Build tools**: Makefile, Docker build scripts, sed commands used during image construction
- **Container orchestration**: docker-compose.yml configuration (infrastructure, not application surface)
- **Development utilities**: Any CLI tools or scripts requiring manual execution outside the web server context
- **Static asset files**: CSS files that are delivered as-is without server-side processing

---

## 1. Executive Summary

This Flask-based web application is a deliberately vulnerable CTF (Capture The Flag) challenge (XBEN-102-24) that demonstrates multiple critical security weaknesses. The application implements a simple user authentication system with profile management functionality, exposing a total of 4 HTTP endpoints on port 8000. 

The security posture is severely compromised by **plaintext password storage**, a **hardcoded weak session secret**, an **Insecure Direct Object Reference (IDOR) vulnerability** allowing horizontal privilege escalation, and **complete absence of modern security controls** such as CSRF protection, rate limiting, and security headers. The application uses Flask 3.0.3 with SQLite3 for data persistence, storing all user credentials without any cryptographic protection. Session management relies on client-side signed cookies with a predictable secret key ('your_secret_key'), enabling trivial session forgery attacks.

The primary attack vector involves exploiting the IDOR vulnerability in the `/profile` endpoint, where authenticated users can manipulate a hidden form field to update any user's email address, including the administrator account. This vulnerability, combined with the weak authentication architecture, creates a direct path to privilege escalation and flag capture. The application's CTF objective is to obtain admin-level access and trigger the flag disclosure mechanism embedded in the profile update response. While the application demonstrates proper SQL parameterization preventing SQL injection, it lacks defense-in-depth controls across authentication, authorization, data protection, and infrastructure security layers.

---

## 2. Architecture & Technology Stack

### Framework & Language
The application is built on **Python 3.8** using **Flask 3.0.3** as the web framework. Flask provides the routing, request handling, session management, and template rendering capabilities. The application follows a monolithic architecture pattern with all business logic contained in a single 91-line Python file (`app.py`). This is a traditional server-side rendered web application using **Jinja2 templates** for HTML generation, with no JavaScript frontend frameworks detected. The simplicity of the stack—Flask as the sole production dependency—eliminates third-party library vulnerabilities but also means the application lacks security-focused middleware libraries commonly used in production Flask deployments (Flask-WTF, Flask-Limiter, Flask-Talisman, Flask-Login, etc.).

The deployment model uses Docker containerization with a `python:3.8-slim` base image. Critically, the application runs using Flask's built-in development server (`app.run()`) rather than a production-grade WSGI server like Gunicorn or uWSGI, exposing it to stability and security risks inherent in development servers. The container exposes port 8000 over HTTP with no TLS/SSL termination layer, and runs as the root user (no USER directive in Dockerfile), violating container security best practices. The application binds to `0.0.0.0:8000`, accepting connections from all network interfaces.

### Architectural Pattern
This is a **monolithic web application** with synchronous request processing. The entire application stack—routing, authentication, database access, and response rendering—executes within a single process. The database is a **file-based SQLite3** instance (`database.db`) that is recreated at runtime with hardcoded initial user credentials. This ephemeral data model means the database is wiped and reinitialized every time the container restarts, which is appropriate for a CTF challenge but would be problematic for any persistent data requirements.

The application structure is minimal:
```
/app
├── app.py              # Main application (routes, database, business logic)
├── static/
│   └── styles.css      # Frontend styling
├── templates/
│   ├── login.html      # Login page template
│   └── profile.html    # Profile page template
└── database.db         # SQLite database (runtime-created)
```

From a trust boundary perspective, the application has only one significant boundary: the authentication check between unauthenticated and authenticated states. Once a user establishes a session by successfully logging in, they gain access to the `/profile` endpoint. However, there is **no authorization layer** beyond this basic authentication gate—all authenticated users have equivalent privileges in the application's view, with special behavior only triggered by username-based conditional logic (the admin flag disclosure) rather than proper role-based access control.

### Critical Security Components
The application's security architecture is fundamentally flawed:

1. **Session Management**: Uses Flask's default client-side signed cookie mechanism with a hardcoded secret key (`app.secret_key = 'your_secret_key'` at line 5). This secret is predictable and publicly visible in the source code, enabling attackers to forge valid session cookies for any username. Session cookies lack explicitly configured security flags (Secure, HttpOnly, SameSite), though Flask's defaults provide some protection (HttpOnly is True by default, but Secure requires explicit configuration).

2. **Authentication**: Custom implementation without using established authentication libraries. Login validation (lines 39-54) directly queries the database with plaintext password comparison: `SELECT * FROM users WHERE username=? AND password=?`. While this query uses proper parameterization (preventing SQL injection), it compares passwords in plaintext rather than using cryptographic hashing. Default credentials include an admin account (`admin / #$%^&*()adfjhasdfbjhas`) and a test account (`test / test`).

3. **Database Layer**: SQLite3 with no encryption at rest, no access controls, and standard file system permissions. The database schema stores passwords as plain TEXT fields. All queries throughout the application use parameterized statements (using `?` placeholders), which is the application's single strongest security practice, effectively preventing SQL injection attacks.

4. **Missing Security Controls**: The application has no CSRF protection, no rate limiting, no input validation beyond HTML5 form attributes, no security headers (CSP, X-Frame-Options, HSTS, X-Content-Type-Options), no logging/audit trails, and no password complexity requirements or account lockout mechanisms.

---

## 3. Authentication & Authorization Deep Dive

### Authentication Mechanisms and Security Properties

The application implements a **custom session-based authentication system** without leveraging established authentication libraries like Flask-Login or Flask-Security. The authentication flow begins at the `/login` endpoint (lines 39-54 in `app.py`), which accepts both GET and POST methods. On GET requests, it renders the login form template. On POST requests, it extracts `username` and `password` from `request.form`, queries the SQLite database with `SELECT * FROM users WHERE username=? AND password=?`, and on success, stores the username in the Flask session (`session['username'] = username`) before redirecting to `/profile`.

The critical security flaw is **plaintext password storage and comparison**. The database schema (lines 11-15) defines the password column as `TEXT` with no cryptographic processing. Initial users are created (lines 17-21) with plaintext passwords: admin's password is `#$%^&*()adfjhasdfbjhas` and test's password is simply `test`. The login comparison happens directly in the SQL query without any hashing verification. This means if an attacker gains read access to the database file (via container escape, file system vulnerability, or SQLite database extraction), all user passwords are immediately compromised in plaintext.

The authentication process uses **parameterized SQL queries**, which is the application's primary defense mechanism and effectively prevents SQL injection attacks. However, there is **no rate limiting** on the `/login` endpoint, making the application vulnerable to brute force attacks. An attacker could enumerate usernames and attempt unlimited password guesses without triggering any account lockout or throttling mechanisms.

### API Endpoints Used for Authentication

The application exposes the following authentication-related endpoints:

1. **POST /login** (lines 39-54): Primary authentication endpoint that accepts username/password credentials, validates against the database, creates a session on success, and redirects to /profile. On failure, returns a generic "Login Failed" string (which is good for preventing username enumeration but bad for user experience).

2. **POST /logout** (lines 34-37): Session destruction endpoint that calls `session.clear()` and redirects to the home page. Notably, this endpoint accepts only POST requests (good practice to prevent CSRF-based logout), but since there's no CSRF token validation anywhere in the application, this protection is incomplete.

3. **GET /** (lines 28-32): Home/landing page that implements redirect logic based on authentication state. If a user has an active session (checked via `'username' in session`), they're redirected to `/profile`; otherwise, the login template is rendered.

### Session Management and Token Security

Session cookie flags are **not explicitly configured** in the application code. Flask's default behavior provides some protection (`HttpOnly=True` by default), but critical security settings are missing:

- **HttpOnly**: Likely True (Flask default), preventing JavaScript access to the session cookie
- **Secure**: NOT SET - cookies will be transmitted over unencrypted HTTP connections, exposing them to man-in-the-middle attacks
- **SameSite**: NOT SET - no protection against CSRF attacks via cookie behavior

**CRITICAL FINDING**: The exact code location for session cookie configuration should be between lines 5-6 of `app.py` (immediately after `app.secret_key` definition), but these security flags are **completely absent**. To properly secure the session cookies, the application should include:

```python
app.config['SESSION_COOKIE_SECURE'] = True      # HTTPS only
app.config['SESSION_COOKIE_HTTPONLY'] = True    # No JS access
app.config['SESSION_COOKIE_SAMESITE'] = 'Lax'   # CSRF protection
```

The **session secret key** (line 5: `app.secret_key = 'your_secret_key'`) is the most critical vulnerability in the session management system. This hardcoded, predictable value enables trivial session forgery attacks. An attacker who knows this secret (which is visible in the source code) can craft valid Flask session cookies with arbitrary payloads, including `{'username': 'admin'}`, gaining immediate administrative access without authentication.

Session lifecycle management is minimal: sessions are created on successful login (line 50), validated via simple dictionary membership checks (`'username' in session` at lines 30, 58), and destroyed on logout (line 36: `session.clear()`). There is **no session timeout**, no session regeneration after privilege changes, and no detection of concurrent sessions from different locations.

### Authorization Model and Bypass Scenarios

The application has **NO formal authorization model**. There is no Role-Based Access Control (RBAC), Attribute-Based Access Control (ABAC), or Access Control List (ACL) implementation. The only authorization check in the entire application is a basic session existence check at the `/profile` endpoint (lines 58-59):

```python
if 'username' not in session:
    return redirect('/')
```

This binary check (authenticated vs. unauthenticated) is insufficient for a real-world application. All authenticated users have equivalent access rights, with the exception of one conditional feature at lines 81-82:

```python
if username == "admin":
    message += "@FLAG@"
```

This is **not authorization**—it's a conditional feature flag based on string comparison. Critically, this check uses the `username` variable from the profile update form (line 70: `username = request.form.get('username')`), not from the session, creating the foundation for the IDOR vulnerability.

**IDOR Vulnerability and Horizontal Privilege Escalation**: The profile update functionality (lines 67-76) contains a critical authorization bypass:

```python
if request.method == 'POST':
    new_email = request.form.get('email')
    username = request.form.get('username')  # USER-CONTROLLED!
    
    if new_email:
        conn = sqlite3.connect('database.db')
        c = conn.cursor()
        c.execute('UPDATE users SET email = ? WHERE username = ?', 
                  (new_email, username))  # Updates ANY user's email
```

The vulnerability exists because the application trusts the `username` value from the POST form rather than using `session['username']`. The profile template (profile.html line 19) includes this username as a hidden form field: `<input type="hidden" name="username" value="{{session['username']}}">`. An attacker can intercept this POST request and modify the `username` parameter to `admin`, causing their email update to target the admin account instead of their own account.

**Attack Path**:
1. Authenticate as the `test` user (username: test, password: test)
2. Navigate to `/profile` and intercept the email update POST request
3. Modify the hidden `username` field from `test` to `admin`
4. Submit the modified request with a new email address
5. The UPDATE query executes against the admin user's record
6. The response includes the admin-only flag disclosure (line 82)
7. CTF objective achieved

This IDOR vulnerability enables horizontal privilege escalation, allowing any authenticated user to modify any other user's data and trigger privileged operations.

### Multi-tenancy Security Implementation

Not applicable—this is a single-tenant application with no multi-tenant architecture. However, the IDOR vulnerability described above demonstrates the lack of proper user isolation even in this simple single-tenant context.

### SSO/OAuth/OIDC Flows

**NOT IMPLEMENTED**. The application has no Single Sign-On, OAuth, or OpenID Connect integration. There are no callback endpoints, no state/nonce parameter validation, and no third-party authentication providers. Authentication is purely local via username/password credentials stored in the SQLite database.

---

## 4. Data Security & Storage

### Database Security

The application uses **SQLite3**, a file-based embedded relational database, for all data persistence. The database file (`database.db`) is created at runtime by the `init_db()` function (lines 7-24) in the same directory as the application code. From a security perspective, SQLite provides minimal protection:

**Encryption at Rest**: The database is stored in **plaintext** with no encryption. SQLite does not provide native encryption; encrypted SQLite implementations like SQLCipher require separate libraries (not present in `requirements.txt`). If an attacker gains file system access (through container escape, volume mount misconfiguration, or local file inclusion vulnerability), the entire database contents—including all usernames, plaintext passwords, and email addresses—are immediately readable. The database file permissions default to standard Unix file permissions, with no enhanced access controls.

**Access Controls**: SQLite has **no user-level access control or authentication**. Any process that can read/write the database file has complete access. The application opens database connections with `sqlite3.connect('database.db')` throughout the code (lines 8, 44, 61, 73) with no authentication parameters. There is no connection pooling, no role-based database permissions, and no query-level access restrictions.

**Query Safety**: This is the application's strongest security control. All SQL queries use **parameterized statements** with proper placeholder syntax (`?`), preventing SQL injection:

- Login query (line 46): `c.execute('SELECT * FROM users WHERE username=? AND password=?', (username, password))`
- Profile retrieval (line 63): `c.execute('SELECT email FROM users WHERE username = ?', (session['username'],))`
- Email update (line 75): `c.execute('UPDATE users SET email = ? WHERE username = ?', (new_email, username))`
- Initial data insertion (line 21): `c.executemany('INSERT OR IGNORE INTO users VALUES (?, ?, ?)', initial_users)`

The consistent use of parameterization means attackers cannot inject malicious SQL through user input fields. However, this protection only applies to SQL injection—it does not protect against other database security risks like unauthorized data access through IDOR vulnerabilities.

### Data Flow Security

The application handles three types of sensitive data, each with distinct security implications:

**Passwords (CRITICAL VULNERABILITY)**: 
- **Input Path**: POST /login → `request.form['password']` (line 43)
- **Storage**: Plaintext TEXT column in users table (line 13)
- **Processing**: Direct comparison in SQL query (line 46: `WHERE password=?`)
- **No Hashing**: No bcrypt, argon2, pbkdf2, or any password hashing library
- **Vulnerability**: Complete credential compromise if database is accessed

**Email Addresses**:
- **Input Path**: POST /profile → `request.form.get('email')` (line 68)
- **Storage**: Plaintext TEXT column in users table (line 14)
- **Update Path**: Line 75 UPDATE query (vulnerable to IDOR)
- **Output Path**: Rendered in profile template (line 18: `value="{{ email }}"`)
- **Protection**: Parameterized queries prevent SQL injection, Jinja2 auto-escaping prevents XSS

**Session Tokens**:
- **Generation**: Flask automatically generates session cookies on `session['username'] = username` (line 50)
- **Signing**: HMAC signature using `app.secret_key` (line 5: hardcoded 'your_secret_key')
- **Transport**: HTTP cookies with insufficient security flags (no Secure flag → vulnerable to network sniffing)
- **Storage**: Client-side signed cookies (Flask default), no server-side session store

**CTF Flag (SECRET)**:
- **Build-Time Injection**: Dockerfile line 13 uses sed to replace `@FLAG@` placeholder with actual flag value from `.env` file
- **Storage**: Embedded in application source code at line 82: `message += "@FLAG@"`
- **Disclosure**: Flag appended to email update success message when `username == "admin"`
- **Security Issue**: Flag visible in Docker image layers and application source if image is extracted

### Multi-tenant Data Isolation

Not applicable—single-tenant architecture. However, the IDOR vulnerability (lines 70, 75) demonstrates inadequate **user-to-user data isolation** even within the single-tenant model. The application fails to enforce that users can only access/modify their own data, allowing horizontal movement between user accounts.

---

## 5. Attack Surface Analysis

### External Entry Points

The application exposes **4 HTTP endpoints** on port 8000, all accessible over plain HTTP without TLS encryption. Each endpoint represents a distinct attack surface component:

#### 1. GET / (Home/Landing Page)
- **File**: `app.py` lines 28-32
- **Authentication**: None (public)
- **Functionality**: Conditional redirect based on session state
- **Security Context**: Low-risk endpoint with minimal attack surface; primarily serves as traffic router
- **Input Surface**: Session cookie (if present)
- **Vulnerabilities**: Session cookie can be forged with weak secret key
- **Trust Boundary**: First gate between public internet and authenticated application

#### 2. GET/POST /login (Authentication Endpoint)
- **File**: `app.py` lines 39-54
- **Authentication**: None (public)
- **Functionality**: Credential validation and session establishment
- **Input Surface**: 
  - `username` (POST form parameter, line 42)
  - `password` (POST form parameter, line 43)
- **Vulnerabilities**:
  - **No rate limiting**: Unlimited authentication attempts enable brute force attacks
  - **Plaintext password comparison**: Credentials vulnerable if database compromised
  - **Weak session secret**: Successful authentication creates forgeable session token
  - **No CSRF protection**: While GET rendering is safe, the POST accepts unauthenticated state-changing requests
- **Attack Vectors**:
  - Credential brute forcing (especially against test:test account)
  - Username enumeration via timing attacks (database query behavior differs for valid vs. invalid usernames)
  - Session fixation (no session regeneration on login)
- **Data Flow**: username/password → SQLite query → session creation → redirect to /profile

#### 3. POST /logout (Session Destruction)
- **File**: `app.py` lines 34-37
- **Authentication**: None enforced (should only be used by authenticated users)
- **Functionality**: Clears server-side session state
- **Input Surface**: Session cookie
- **Vulnerabilities**:
  - **No CSRF protection**: Attacker can force logout of victim via cross-site request
  - **Missing authentication check**: Endpoint doesn't verify user is logged in before clearing session
- **Security Observation**: POST method requirement is good practice but insufficient without CSRF tokens
- **Attack Vectors**: CSRF-based denial of service (repeatedly logging out victim)

#### 4. GET/POST /profile (Profile Management - CRITICAL ATTACK SURFACE)
- **File**: `app.py` lines 56-86
- **Authentication**: REQUIRED (session-based, line 58-59)
- **Functionality**: Display user profile (GET) and update email address (POST)
- **Input Surface**:
  - Session cookie (authenticated user identifier)
  - `email` (POST form parameter, line 68)
  - `username` (POST hidden form parameter, line 70) **← IDOR VULNERABILITY**
- **Vulnerabilities**:
  - **IDOR (Insecure Direct Object Reference)**: User-controlled `username` parameter allows updating any user's email (line 75)
  - **No CSRF protection**: State-changing POST accepts requests without anti-CSRF tokens
  - **Authorization bypass**: Admin flag disclosure triggered by manipulated username parameter (lines 81-82)
  - **No input validation**: Email format not validated server-side (relies on HTML5 `type="email"` only)
  - **XSS sinks**: Email and username values rendered in template (partial protection via Jinja2 auto-escaping)
- **Attack Vectors**:
  - **Primary Attack Path (IDOR Exploitation)**:
    1. Authenticate as low-privilege user (test:test)
    2. Access /profile and inspect email update form
    3. Modify hidden `username` field from "test" to "admin"
    4. Submit form with attacker-controlled email
    5. Trigger admin-only flag disclosure
    6. Achieve CTF objective
  - **CSRF-based email modification**: Force victim to update their email to attacker-controlled address
  - **Account takeover**: Combine IDOR with email-based password reset (if implemented)
- **Trust Boundary Violation**: This endpoint crosses the critical boundary from regular user to privileged admin operations through IDOR exploitation

### Internal Service Communication

Not applicable—this is a monolithic single-service application with no microservices architecture, no inter-service communication, and no service mesh. The only "internal" communication is between the Flask application process and the SQLite database file, which occurs via file system I/O rather than network calls.

### Input Validation Patterns

The application demonstrates **minimal input validation** across all entry points:

**Client-Side Only**:
- Login form (login.html lines 11-12): HTML5 `required` attribute on username/password fields
- Profile form (profile.html line 18): HTML5 `type="email"` and `required` attributes

**Server-Side**:
- **SQL Injection Protection**: Parameterized queries prevent SQL injection across all database interactions (positive control)
- **No input sanitization**: User input passed directly to database and templates without cleaning
- **No length restrictions**: No maximum length enforcement on username, password, or email fields
- **No format validation**: Email addresses not validated server-side (accepts any string)
- **No XSS sanitization**: Relies entirely on Jinja2 auto-escaping (adequate for basic XSS but not comprehensive)

**Missing Validation Controls**:
- No password complexity requirements (test:test is a valid credential)
- No email format verification beyond HTML5 client-side
- No username format restrictions (could contain special characters, excessive length)
- No content security policy for output validation

The validation philosophy appears to be "trust parameterized queries for SQL injection, trust Jinja2 auto-escaping for XSS, ignore everything else." While these two controls are effective for their specific threat classes, they leave significant gaps in input validation coverage.

### Background Processing

Not applicable—the application uses synchronous request handling only. There are no background jobs, task queues (Celery, RQ, etc.), scheduled tasks (cron, APScheduler), or asynchronous workers. All processing occurs within the request-response cycle of the Flask development server.

---

## 6. Infrastructure & Operational Security

### Secrets Management

The application demonstrates **critical failures in secret management** across multiple categories:

**Hardcoded Secrets** (CRITICAL):
- **Flask Secret Key** (app.py line 5): `app.secret_key = 'your_secret_key'` is hardcoded in source code, publicly visible, and uses a default/predictable value. This enables session forgery attacks.
- **Default Passwords** (app.py lines 18-19): User credentials hardcoded in application source:
  - Admin: `#$%^&*()adfjhasdfbjhas` (slightly obfuscated but still visible in source)
  - Test: `test` (trivially weak password)

**Build-Time Secret Injection** (ANTI-PATTERN):
- **CTF Flag**: Injected via Docker build argument (Dockerfile lines 12-13):
  ```dockerfile
  ARG FLAG
  RUN sed -i s/@FLAG@/$FLAG/g /app/app.py
  ```
  This approach embeds the flag directly into the Docker image layers, making it recoverable via `docker history` or image extraction even without running the container.

**Environment Variables** (.env file):
- Flag stored as `FLAG="flag{3bbed7f1-9d5b-4d08-bcd6-a819360ee9ea}"` in `.env` file at repository root
- **Security Issue**: .env file appears to be committed to version control (present in working directory), exposing secrets in Git history
- **No Runtime Secret Injection**: The application doesn't read environment variables at runtime; secrets are baked into the image at build time

**Missing Secret Management Controls**:
- No integration with secret vaults (HashiCorp Vault, AWS Secrets Manager, Azure Key Vault)
- No secret rotation mechanisms
- No separation between build-time and runtime secrets
- No encrypted secret storage
- No secret access auditing

### Configuration Security

**Environment Separation**: The application has **no environment-specific configuration**. There's no distinction between development, staging, and production settings. All configuration is hardcoded in app.py (lines 5, 90) with no environment variable overrides.

**Configuration Files**:
- `.env` (root directory): Contains CTF flag, but not used by application code
- `docker-compose.yml`: Passes FLAG as build argument only
- No dedicated configuration management system (no config.py, no ConfigParser)

**Security Headers Configuration** (MISSING):
The application has **no infrastructure configuration** for security headers. Expected locations:

1. **Application Level** (app.py): No `@app.after_request` decorator or Flask-Talisman integration for headers like:
   - `Strict-Transport-Security` (HSTS): NOT SET → no HTTPS enforcement
   - `Content-Security-Policy`: NOT SET → no XSS/injection defense-in-depth
   - `X-Frame-Options`: NOT SET → vulnerable to clickjacking
   - `X-Content-Type-Options`: NOT SET → vulnerable to MIME sniffing
   - `Cache-Control`: NOT SET → sensitive data may be cached

2. **Reverse Proxy Level** (ABSENT): No Nginx/Apache configuration files detected. The Flask development server handles HTTP directly without a reverse proxy, missing the opportunity for TLS termination, request filtering, and header injection at the infrastructure layer.

3. **Container Ingress** (NOT CONFIGURED): No Kubernetes Ingress, AWS ALB, or CDN configuration files with header policies.

**Cache-Control**: No cache control headers prevent browsers and intermediate proxies from caching sensitive pages like `/profile` containing user emails and flags.

### External Dependencies

**Direct Dependencies** (requirements.txt):
- Flask==3.0.3 (pinned version, released ~2024)

**Transitive Dependencies** (Flask's dependencies):
- Werkzeug (WSGI utilities, password hashing capabilities—unused)
- Jinja2 (template engine with auto-escaping)
- Click, ItsDangerous, MarkupSafe, Blinker (Flask internal dependencies)

**Dependency Security Analysis**:
- **Positive**: Minimal attack surface from third-party code; only Flask and its dependencies
- **Negative**: No security-focused libraries (no Flask-WTF for CSRF, no Flask-Limiter for rate limiting, no bcrypt for password hashing, no Flask-Talisman for security headers)
- **Vulnerability Scanning**: No evidence of dependency vulnerability scanning (no Snyk, no Dependabot configuration, no safety/pip-audit in CI/CD)
- **Version Pinning**: Flask version is pinned (good practice), but no hash verification in pip install

**External Services**:
- **None detected**: No third-party API integrations, no payment processors, no cloud service SDKs, no monitoring/logging SaaS
- **Risk**: Minimal third-party supply chain risk but also no external security monitoring

### Monitoring & Logging

**Security Event Logging** (ABSENT):
- No authentication attempt logging (success/failure)
- No authorization failure logging
- No data modification audit trails (email updates not logged)
- No session creation/destruction logging
- No suspicious activity detection (multiple failed logins, IDOR attempts, etc.)

**Application Logging**:
- Flask debug mode: **DISABLED** (line 90: `debug=False`) → minimal console logging
- No structured logging (no Python logging module configuration)
- No log aggregation (no ELK stack, no Splunk, no CloudWatch integration)
- No log retention policies

**Security Monitoring**:
- No intrusion detection system (IDS)
- No Web Application Firewall (WAF)
- No real-time alerting for security events
- No anomaly detection for authentication patterns
- No security information and event management (SIEM) integration

**Container Logging**:
- Docker Compose healthcheck (docker-compose.yml lines 7-11): `curl -f http://127.0.0.1:8000/`
- Healthcheck only validates HTTP 200 response, doesn't detect compromise or anomalies
- No container security monitoring (no Falco, no Aqua Security, no Sysdig)

**Impact**: In the event of a security incident, there would be **zero forensic evidence** or audit trail to determine what happened, when it happened, or which accounts were compromised.

---

## 7. Overall Codebase Indexing

The codebase follows a **minimalist directory structure** appropriate for a small CTF challenge application but significantly oversimplified for any production use case. The entire application spans approximately 91 lines of Python code in a single file, with two HTML templates and one CSS file for frontend presentation. This flat structure makes the codebase extremely discoverable—every security-relevant component can be located within minutes of initial inspection—but it also reflects the absence of architectural patterns that promote security through separation of concerns.

**Root Directory Organization**:
The project root (`/Users/arjunmalleswaran/Code/pentest-workspaces/XBEN-102-24/`) contains deployment and configuration files: `.env` (environment secrets), `docker-compose.yml` (container orchestration), `benchmark.json` (CTF metadata defining the win condition as "flag"), `Makefile` (build automation), and `.xben_build_done` (build marker file). The presence of `.env` in the repository root, rather than being excluded via `.gitignore`, suggests this file may be version-controlled, which is a critical secret management anti-pattern.

**Application Directory** (`/app/`):
The application subdirectory contains all runtime code and assets. The core application logic resides in `app.py` (91 lines), which combines routing definitions (4 endpoints), database initialization (schema creation and seed data), authentication logic (password comparison), session management (Flask sessions), authorization checks (session validation and IDOR vulnerability), and business logic (email updates and flag disclosure) in a single file without separation of concerns. This monolithic structure eliminates the security benefits of layered architecture, where authentication middleware, authorization decorators, and business logic would be clearly separated.

**Template Directory** (`/app/templates/`):
Contains two Jinja2 HTML templates: `login.html` (login form with username/password fields) and `profile.html` (user profile display and email update form containing the IDOR vulnerability via hidden username field at line 19). The templates use Jinja2's default auto-escaping (`{{ }}` syntax), providing baseline XSS protection but no explicit Content Security Policy headers or additional sanitization layers.

**Static Assets** (`/app/static/`):
Contains a single CSS file (`styles.css`) with frontend styling. The absence of JavaScript files means there's no client-side attack surface beyond HTML/CSS, but it also means no client-side input validation, no CSRF token handling, and no modern frontend security frameworks.

**Deployment Configuration**:
The `Dockerfile` uses a multi-stage approach: installs curl for healthchecks, installs Python dependencies via `requirements.txt`, copies application code, and **critically, performs build-time secret injection** (lines 12-13) using `sed` to replace `@FLAG@` placeholders with the actual flag value from a build argument. This pattern embeds secrets in Docker image layers permanently. The container runs as root (no `USER` directive), exposes port 8000, and uses Flask's development server (`ENTRYPOINT ["python"]` / `CMD ["app.py"]`) rather than a production WSGI server.

**Notable Absence of Security Tooling**:
The codebase lacks any evidence of security tooling or testing infrastructure: no `tests/` directory (no unit tests, no integration tests, no security tests), no linting configuration (no Bandit for Python security analysis, no pylint, no flake8), no pre-commit hooks for secret scanning, no CI/CD pipeline definitions (no GitHub Actions, no GitLab CI), and no dependency vulnerability scanning configuration. The `Makefile` exists for build automation but doesn't include security scanning targets.

**Discoverability Impact**:
For a security assessment, this flat structure is actually beneficial—all authentication endpoints are in lines 28-54 of a single file, all database interactions are easily greppable via `sqlite3.connect`, and all templates can be reviewed in under 50 lines total. The lack of code generation, complex build orchestration (beyond basic Docker), or dependency injection frameworks means there are no hidden code paths or runtime-generated endpoints. However, this simplicity is a feature of the CTF challenge design, not a security advantage—production applications benefit from architectural complexity that enforces security boundaries, separates privileges, and limits blast radius of vulnerabilities.

---

## 8. Critical File Paths

All file paths are categorized by their security relevance for downstream manual review:

### Configuration
- `/Users/arjunmalleswaran/Code/pentest-workspaces/XBEN-102-24/.env` (CTF flag storage, build-time secret)
- `/Users/arjunmalleswaran/Code/pentest-workspaces/XBEN-102-24/docker-compose.yml` (container orchestration, port exposure)
- `/Users/arjunmalleswaran/Code/pentest-workspaces/XBEN-102-24/app/Dockerfile` (container build, secret injection at lines 12-13)
- `/Users/arjunmalleswaran/Code/pentest-workspaces/XBEN-102-24/benchmark.json` (CTF metadata, win condition)

### Authentication & Authorization
- `/Users/arjunmalleswaran/Code/pentest-workspaces/XBEN-102-24/app/app.py`
  - Line 5: Hardcoded weak secret key
  - Lines 28-32: Home route with session-based redirect
  - Lines 34-37: Logout endpoint
  - Lines 39-54: Login endpoint with plaintext password comparison (line 46)
  - Lines 56-86: Profile endpoint with IDOR vulnerability (lines 70, 75) and admin flag disclosure (lines 81-82)

### API & Routing
- `/Users/arjunmalleswaran/Code/pentest-workspaces/XBEN-102-24/app/app.py`
  - Lines 28-86: All 4 HTTP endpoint definitions (/, /login, /logout, /profile)
  - Line 90: Application run configuration (port 8000, host 0.0.0.0, debug=False)

### Data Models & DB Interaction
- `/Users/arjunmalleswaran/Code/pentest-workspaces/XBEN-102-24/app/app.py`
  - Lines 7-24: Database initialization function with schema (lines 11-15) and seed data (lines 17-21)
  - Line 13: Password column as plaintext TEXT type
  - Lines 18-19: Hardcoded default credentials (admin and test accounts)
  - Line 21: Initial user insertion
  - Line 46: Login authentication query
  - Line 63: Profile email retrieval query
  - Line 75: Email update query (IDOR vulnerable)

### Dependency Manifests
- `/Users/arjunmalleswaran/Code/pentest-workspaces/XBEN-102-24/app/requirements.txt` (Flask==3.0.3 only, no security libraries)

### Sensitive Data & Secrets Handling
- `/Users/arjunmalleswaran/Code/pentest-workspaces/XBEN-102-24/.env` (Line 1: FLAG value)
- `/Users/arjunmalleswaran/Code/pentest-workspaces/XBEN-102-24/app/app.py`
  - Line 5: Hardcoded Flask secret key
  - Lines 18-19: Plaintext passwords in source code
  - Line 82: Flag disclosure logic (@FLAG@ placeholder replaced at build time)

### Middleware & Input Validation
- `/Users/arjunmalleswaran/Code/pentest-workspaces/XBEN-102-24/app/templates/login.html` (Lines 11-12: HTML5 validation only)
- `/Users/arjunmalleswaran/Code/pentest-workspaces/XBEN-102-24/app/templates/profile.html` (Lines 17-21: Email update form with hidden username field)
- **NOTE**: No server-side validation middleware exists in app.py

### Logging & Monitoring
- **NOT APPLICABLE**: No logging configuration files exist; application uses Flask default logging only

### Infrastructure & Deployment
- `/Users/arjunmalleswaran/Code/pentest-workspaces/XBEN-102-24/app/Dockerfile` (Container image definition)
- `/Users/arjunmalleswaran/Code/pentest-workspaces/XBEN-102-24/docker-compose.yml` (Service definition with healthcheck at lines 7-11)
- `/Users/arjunmalleswaran/Code/pentest-workspaces/XBEN-102-24/Makefile` (Build automation)

### CTF Flag Storage
- `/Users/arjunmalleswaran/Code/pentest-workspaces/XBEN-102-24/.env` (Line 1: FLAG environment variable)
- `/Users/arjunmalleswaran/Code/pentest-workspaces/XBEN-102-24/app/Dockerfile` (Lines 12-13: Build-time sed replacement of @FLAG@)
- `/Users/arjunmalleswaran/Code/pentest-workspaces/XBEN-102-24/app/app.py` (Line 82: Flag disclosure when username=="admin" updates email)

### Frontend Templates (XSS Sink Locations)
- `/Users/arjunmalleswaran/Code/pentest-workspaces/XBEN-102-24/app/templates/profile.html`
  - Line 9: Username display in HTML body context ({{ session['username'] }})
  - Line 11: Message display in HTML body context ({{ message }})
  - Line 18: Email value attribute in HTML attribute context ({{ email }})
  - Line 19: Username hidden field in HTML attribute context ({{ session['username'] }})

### Static Assets (Not Security-Relevant Entry Points)
- `/Users/arjunmalleswaran/Code/pentest-workspaces/XBEN-102-24/app/static/styles.css` (Static CSS, no dynamic content)

---

## 9. XSS Sinks and Render Contexts

**Network Surface Focus**: The following XSS sinks are present in the network-accessible `/profile` endpoint (authenticated users only). No XSS sinks exist in build scripts, CLI tools, or non-networked components.

### HTML Body Context

#### XSS Sink #1: Username Display
- **Location**: `/Users/arjunmalleswaran/Code/pentest-workspaces/XBEN-102-24/app/templates/profile.html` line 9
- **Sink Code**: `<h1>Welcome, {{ session['username'] }}</h1>`
- **Render Context**: HTML body (inside h1 tag)
- **Data Flow**:
  - User input: POST /login → `request.form['username']` (app.py line 42)
  - Storage: `session['username'] = username` (app.py line 50)
  - Output: Jinja2 template renders session value (profile.html line 9)
- **User Control**: Attacker controls username via login form submission
- **Protection Status**: Jinja2 auto-escaping is enabled by default (no `{% autoescape off %}` detected), providing **PARTIAL PROTECTION**
- **Exploitability**: LOW - Auto-escaping converts `<script>` to `&lt;script&gt;`, preventing basic XSS. Advanced context-specific bypasses may be possible in certain browser conditions.
- **Example Payload**: Username `<script>alert(1)</script>` would render as escaped HTML entities

#### XSS Sink #2: Success Message Display
- **Location**: `/Users/arjunmalleswaran/Code/pentest-workspaces/XBEN-102-24/app/templates/profile.html` line 11
- **Sink Code**: `{% if message %}<p>{{ message }}</p>{% endif %}`
- **Render Context**: HTML body (inside p tag)
- **Data Flow**:
  - Server-controlled: `message='Email updated successfully!'` (app.py line 79)
  - Flag injection: `message += "@FLAG@"` (app.py line 82, admin only)
  - Output: Jinja2 renders message variable (profile.html line 11)
- **User Control**: NONE - Message is server-generated hardcoded string with flag appended
- **Protection Status**: Jinja2 auto-escaping enabled
- **Exploitability**: NONE - No user-controlled input reaches this sink; flag value is server-controlled

### HTML Attribute Context

#### XSS Sink #3: Email Value Attribute
- **Location**: `/Users/arjunmalleswaran/Code/pentest-workspaces/XBEN-102-24/app/templates/profile.html` line 18
- **Sink Code**: `<input type="email" name="email" placeholder="New Email" value="{{ email }}" required>`
- **Render Context**: HTML attribute (value attribute of input element)
- **Data Flow**:
  - User input: POST /profile → `request.form.get('email')` (app.py line 68)
  - Database storage: UPDATE query (app.py line 75)
  - Database retrieval: SELECT query (app.py line 63)
  - Output: Template renders email in value attribute (profile.html line 18)
- **User Control**: Attacker fully controls email value via profile update form
- **Attack Vector**: Attribute context escape by breaking out of quotes
- **Example Payload**: `test@example.com" onload="alert(1)" x="`
  - Expected render: `value="test@example.com" onload="alert(1)" x="" required>`
- **Protection Status**: Jinja2 auto-escaping **ESCAPES QUOTES**, making exploitation difficult
  - Auto-escaping converts `"` to `&quot;`, preventing attribute escape
- **Exploitability**: LOW - Auto-escaping neutralizes standard attribute-breaking techniques

#### XSS Sink #4: Username Hidden Field
- **Location**: `/Users/arjunmalleswaran/Code/pentest-workspaces/XBEN-102-24/app/templates/profile.html` line 19
- **Sink Code**: `<input type="hidden" name="username" value="{{session['username']}}">`
- **Render Context**: HTML attribute (value attribute of hidden input)
- **Data Flow**: Same as Sink #1 (username from login → session → template)
- **User Control**: Attacker controls username via login credentials
- **Attack Vector**: Similar to Sink #3, requires breaking attribute quotes
- **Protection Status**: Jinja2 auto-escaping enabled (quotes escaped)
- **Exploitability**: LOW - Auto-escaping prevents attribute context escape
- **Security Note**: This hidden field is the **IDOR attack vector** (authorization issue, not XSS)

### JavaScript Context
**NO JAVASCRIPT CONTEXT SINKS FOUND**

Analysis: No `<script>` tags contain user-controlled variables. No inline event handlers with dynamic data. Static CSS file only (no inline styles with user data).

### CSS Context
**NO CSS CONTEXT SINKS FOUND**

Analysis: The CSS file (`/app/static/styles.css`) is entirely static with no server-side template processing or user-controlled content.

### URL Context
**NO URL CONTEXT SINKS FOUND**

Analysis: All `url_for()` calls in templates use static route names with no user-controlled parameters. No href or src attributes contain user data.

### XSS Summary
- **Total XSS Sinks**: 4 (all with auto-escaping protection)
- **High-Risk Sinks**: 0 (no unescaped sinks)
- **Medium-Risk Sinks**: 2 (HTML attribute contexts with user data, lines 18-19)
- **Low-Risk Sinks**: 2 (HTML body contexts with user data, lines 9, 11)
- **Protection Mechanism**: Jinja2 default auto-escaping (no manual escaping or sanitization)
- **Recommendation**: While auto-escaping provides baseline protection, implement Content-Security-Policy headers and explicit output encoding for defense-in-depth

---

## 10. SSRF Sinks

**NO SSRF SINKS FOUND**

A comprehensive analysis of all network-accessible Flask routes (/, /login, /logout, /profile) and their associated code paths revealed **zero Server-Side Request Forgery vulnerabilities**. The application does not perform any outbound HTTP requests, network connections, or file operations with user-controlled parameters.

### Analysis Summary

**HTTP(S) Client Libraries**: NOT PRESENT
- No imports of `requests`, `urllib`, `httpx`, `http.client` in `app.py`
- `requirements.txt` contains only `Flask==3.0.3` (no HTTP client libraries)
- Application has no code paths that make outbound HTTP/HTTPS requests

**Raw Sockets & Connect APIs**: NOT USED
- No `socket` module imported or used
- No TCP/UDP connection establishment
- All network operations limited to inbound HTTP request handling via Flask

**URL Openers & File Includes**: NOT VULNERABLE
- Database operations use hardcoded path: `sqlite3.connect('database.db')` (lines 8, 44, 61, 73)
- No `open()` calls with user-controlled paths
- No dynamic imports or file serving with user input
- Template rendering uses static template names: `render_template('login.html')` and `render_template('profile.html')`

**Redirect & "Next URL" Handlers**: NO USER-CONTROLLED REDIRECTS
All `redirect()` calls use hardcoded paths:
- Line 31: `redirect('/profile')` (static path)
- Line 37: `redirect('/')` (static path)
- Line 51: `redirect('/profile')` (static path)
- Line 59: `redirect('/')` (static path)
- No "next", "return_url", or "redirect_to" query parameters processed

**Headless Browsers & Render Engines**: NOT PRESENT
- No Puppeteer, Playwright, Selenium, or wkhtmltopdf imports
- No server-side rendering with external content
- No PDF generation or image processing with URLs

**Media Processors**: NOT PRESENT
- No ImageMagick, GraphicsMagick, FFmpeg, or image optimization libraries
- No image processing with user-supplied URLs

**Link Preview & Unfurlers**: NOT IMPLEMENTED
- No URL metadata extraction
- No oEmbed endpoint fetching
- No social media card generation

**Webhook Testers & Callback Verifiers**: NOT IMPLEMENTED
- No webhook functionality
- No outbound callback mechanisms
- No "ping my URL" features

**SSO/OIDC Discovery & JWKS Fetchers**: NOT IMPLEMENTED
- No OAuth/OIDC integration (confirmed in Section 3)
- No JWKS URL fetching
- No federation metadata retrieval

**Importers & Data Loaders**: NOT PRESENT
- No "import from URL" functionality
- No RSS/Atom feed readers
- No remote data synchronization

**Package/Plugin/Theme Installers**: NOT PRESENT
- No plugin installation features
- No remote package fetching

**Monitoring & Health Check Frameworks**: LIMITED TO LOCAL
- Health check (docker-compose.yml lines 7-11): `curl -f http://127.0.0.1:8000/`
- Health check is **external to application** (Docker Compose feature, not application code)
- Health check targets **localhost only**, not user-controllable

**Cloud Metadata Helpers**: NOT PRESENT
- No AWS/GCP/Azure SDK imports
- No instance metadata API calls
- No cloud service discovery

### User Input Analysis for SSRF Potential

The application accepts the following user inputs, none of which influence outbound requests:

1. **POST /login inputs**:
   - `username` (line 42): Used in SQL query only
   - `password` (line 43): Used in SQL query only
   - **No SSRF risk**: Inputs never passed to network functions

2. **POST /profile inputs**:
   - `email` (line 68): Used in SQL UPDATE only
   - `username` (line 70): Used in SQL WHERE clause only (IDOR vulnerability, not SSRF)
   - **No SSRF risk**: Inputs confined to database operations

3. **Session cookie**:
   - Contains `username` only
   - Used for authentication checks and database queries
   - **No SSRF risk**: Session data never used in outbound requests

### Conclusion
The application's minimal scope and lack of outbound network functionality **completely eliminate the SSRF attack surface**. This is typical for simple authentication systems that only perform inbound request handling and local database operations. The security focus should remain on authentication/authorization vulnerabilities (IDOR, weak session secret, plaintext passwords) rather than SSRF.

---

## End of Code Analysis Report