# SSRF Analysis Report

## 1. Executive Summary
- **Analysis Status:** Complete
- **Key Outcome:** Zero server-side request forgery (SSRF) vulnerabilities identified. The application architecture contains no functionality that makes outbound HTTP requests.
- **Purpose of this Document:** This report confirms the complete absence of SSRF attack surface in the PHP blog application and documents why SSRF vulnerabilities are not possible given the current feature set and implementation.

## 2. Dominant Vulnerability Patterns

### Pattern: No Outbound HTTP Request Functionality

**Observation:** The application is a minimalist PHP blog platform that implements only basic CRUD operations against a local MySQL database. The entire codebase consists of two PHP files (`index.php` and `admin.php`) with a total of 132 lines of code, none of which make server-side HTTP requests.

**Architectural Characteristics:**
- **No HTTP Client Libraries:** The application does not use curl, file_get_contents with URLs, fopen with URL wrappers, or any third-party HTTP client libraries (Guzzle, Symfony HttpClient, etc.)
- **No Network Socket Functions:** No usage of fsockopen, pfsockopen, socket_connect, or raw socket operations
- **No External Service Integrations:** No OAuth providers, payment gateways, webhooks, API proxies, or third-party service calls
- **No URL Processing Features:** No link preview generation, metadata fetching, RSS feed parsing, or remote resource loading
- **Hardcoded Database Connections:** MySQL connections use hardcoded credentials (`new mysqli('db', 'user', 'password', 'blogDB')`) with no user-controllable parameters

**Implication:** SSRF vulnerabilities are architecturally impossible in the current implementation. The application has no code paths that could be manipulated to make the server fetch arbitrary URLs or connect to arbitrary network endpoints.

**Representative Findings:** N/A - No SSRF vulnerabilities exist

## 3. Strategic Intelligence for Exploitation

### Application Architecture

**HTTP Client Library:** None present

**Request Architecture:** 
- The application only processes **inbound HTTP requests** (users accessing the web server on port 39001)
- Database queries are made to a **hardcoded internal MySQL server** (hostname: `db`, port: 3306, Docker network only)
- Static images are served by Apache directly from the filesystem (`/var/www/html/images/`)
- The `<img src='images/{$row['image']}'>` HTML tag in index.php generates **client-side browser requests**, not server-side fetches

**Internal Services:** 
- MySQL database server accessible only via Docker bridge network (not exposed externally)
- No other internal services, APIs, or microservices exist

**Feature Set Analysis:**
The application implements only these features:
1. **Blog Post Display** (`GET /index.php`) - Queries local MySQL, renders HTML
2. **Admin Authentication** (`POST /admin.php`) - Validates credentials against local database
3. **Static File Serving** - Apache serves CSS and JPEG files from filesystem

**Missing Features That Would Create SSRF Risk:**
- ❌ Webhook functionality (no callback URLs)
- ❌ URL fetching/preview (no remote resource loading)
- ❌ OAuth/OIDC flows (no JWKS fetching, no external identity providers)
- ❌ API proxy functionality (no URL parameters that trigger server-side requests)
- ❌ Image import from URL (images are static files only)
- ❌ RSS/Atom feed parsing (no feed readers)
- ❌ Email/SMTP functionality (no mail functions)
- ❌ File upload from URL (no remote file imports)
- ❌ External API integrations (no third-party services)

### Code Analysis Summary

**Files Analyzed:**
- `/app/html/index.php` (73 lines) - Blog listing page
- `/app/html/admin.php` (59 lines) - Admin login and authentication

**Search Results for SSRF-Related Functions:**

| Function Category | Functions Searched | Instances Found | Files |
|------------------|-------------------|-----------------|-------|
| curl functions | curl_init, curl_exec, curl_multi_exec, curl_setopt | 0 | None |
| URL file operations | file_get_contents, fopen, readfile | 0 | None |
| Network sockets | fsockopen, pfsockopen, socket_connect, socket_create | 0 | None |
| Stream contexts | stream_context_create, stream_socket_client | 0 | None |
| HTTP wrappers | allow_url_fopen usage, allow_url_include usage | 0 | None |
| Image processing | getimagesize with URLs, imagecreatefrom* with URLs | 0 | None |
| XML processing | simplexml_load_file, DOMDocument::load with URLs | 0 | None |
| Include with URLs | include, require with http:// or https:// | 0 | None |
| Third-party clients | Guzzle, Symfony HttpClient, Requests library | 0 | None |

**User Input Parameters Analyzed:**

| Parameter | Location | Purpose | Flows To | SSRF Risk |
|-----------|----------|---------|----------|-----------|
| `$_POST['username']` | /admin.php:17 | Admin login | SQL query (line 20) | None (SQL injection, not SSRF) |
| `$_POST['password']` | /admin.php:18 | Admin login | MD5 hash → SQL query | None (SQL injection, not SSRF) |
| `$_GET['category']` | /index.php:37 | Blog filtering | **DISABLED** (hardcoded to empty string) | None (disabled feature) |

**Database Connection Analysis:**

```php
// index.php line 2:
$conn = new mysqli('db', 'user', 'password', 'blogDB');

// admin.php line 12:
$conn = new mysqli('db', 'user', 'password', 'blogDB');
```

**Analysis:** All four mysqli parameters are hardcoded string literals. No user input influences the hostname, port, username, password, or database name. This is not exploitable for SSRF.

**Image Reference Analysis:**

```php
// index.php line 61:
<img src='images/{$row['image']}' alt='{$row['title']}' style='width:200px;height:200px;'/>
```

**Analysis:** 
- `$row['image']` contains filenames from the database (`'morning-dew.jpg'`, `'sunset.jpg'`)
- The `<img>` tag generates a **client-side HTTP request** from the user's browser
- Apache serves static files from `/var/www/html/images/` directory
- The server does NOT make any outbound request to fetch the image
- This is **NOT** an SSRF vector (client-side request, not server-side)

## 4. Secure by Design: Validated Components

The application has no SSRF-vulnerable components to validate. However, the following architectural decisions inherently prevent SSRF:

| Component/Flow | Endpoint/File Location | Defense Mechanism Implemented | Verdict |
|---|---|---|---|
| Database Connectivity | `/app/html/index.php:2`, `/app/html/admin.php:12` | Hardcoded connection parameters (hostname, credentials). No user input influences mysqli connection string. | SAFE (Not exploitable for SSRF) |
| Image Serving | `/app/html/index.php:61` | Client-side image loading via HTML `<img>` tags. Server serves static files from filesystem only; no server-side fetching of remote URLs. | SAFE (Client-side request, not server-side) |
| Static Asset Delivery | Apache serving `/styles.css`, `/images/*.jpg` | Apache DirectoryIndex and static file serving. No dynamic URL generation or remote resource fetching. | SAFE (No server-side requests) |
| Blog Post Retrieval | `/app/html/index.php:40-67` | Direct MySQL queries to local database. All data rendered from local database; no external API calls or URL fetching. | SAFE (No outbound requests) |
| Authentication Flow | `/app/html/admin.php:11-31` | Local database credential validation. No OAuth, no external identity providers, no JWKS fetching. | SAFE (No external authentication services) |

### Why This Application Is Secure Against SSRF

**1. Minimal Feature Set:** The application implements only basic blog display and authentication. It lacks modern web application features that commonly introduce SSRF vulnerabilities (webhooks, API integrations, OAuth flows, link previews, file imports from URLs).

**2. No HTTP Client Code:** A comprehensive code audit found zero instances of PHP functions capable of making outbound HTTP requests (curl, file_get_contents with URLs, fopen with URL wrappers, socket functions, third-party HTTP libraries).

**3. No URL Processing:** The application does not accept, parse, or process URLs from user input. The only user inputs are:
   - Authentication credentials (username/password) used in SQL queries
   - A disabled category filter (currently hardcoded to empty string)

**4. Hardcoded Infrastructure:** Database connections use hardcoded hostnames and credentials. Even the Docker Compose environment variables (MYSQL_HOST, MYSQL_USER, etc.) are **defined but unused** by the application code.

**5. Client-Side Asset Loading:** The only network requests related to images are client-side browser requests generated by HTML `<img>` tags. The server never fetches remote resources.

## 5. Analysis Completeness

### Endpoints Analyzed

All network-accessible endpoints from the reconnaissance deliverable were systematically analyzed:

| Endpoint | Method | Functionality | SSRF Sinks Found |
|----------|--------|---------------|------------------|
| `/` or `/index.php` | GET | Blog post listing | 0 |
| `/index.php?category={cat}` | GET | Category filtering (disabled) | 0 |
| `/admin.php` | GET | Login form display | 0 |
| `/admin.php` | POST | Authentication handler | 0 |
| `/styles.css` | GET | Static CSS file | 0 (static asset) |
| `/images/*.jpg` | GET | Static image files | 0 (static asset) |

**Total Endpoints Analyzed:** 6  
**Total SSRF Vulnerabilities Found:** 0

### SSRF Attack Surface Checklist

The following SSRF attack vectors were systematically evaluated:

- ✅ **URL Parameters:** No parameters accept URLs (no `url=`, `callback=`, `webhook=`, `fetch=`, etc.)
- ✅ **Webhook Functionality:** Not implemented
- ✅ **OAuth/OIDC Flows:** Not implemented (no external identity providers)
- ✅ **API Proxy Features:** Not implemented (no request forwarding)
- ✅ **Link Preview/Metadata Fetching:** Not implemented
- ✅ **RSS/Atom Feed Parsing:** Not implemented
- ✅ **Image Import from URL:** Not implemented (static files only)
- ✅ **File Upload from URL:** Not implemented
- ✅ **Email/SMTP Functionality:** Not implemented
- ✅ **XML External Entity Processing:** Not implemented (no XML parsing)
- ✅ **Database Connection String Manipulation:** Not possible (hardcoded parameters)
- ✅ **Redirect Abuse:** No user-controlled redirects exist
- ✅ **Third-Party API Calls:** Not implemented

**Result:** Zero SSRF attack surface across all evaluated vectors.

### Methodology Compliance

This analysis followed the SSRF Analysis Methodology defined in the engagement instructions:

1. **✅ Identify HTTP Client Usage Patterns:** Searched for curl, file_get_contents, fopen, stream functions, third-party libraries. Result: None found.

2. **✅ Protocol and Scheme Validation:** No URL processing exists, so protocol validation is not applicable. Result: N/A.

3. **✅ Hostname and IP Address Validation:** No user-controlled hostnames. Database hostname is hardcoded to `'db'`. Result: Safe by design.

4. **✅ Port Restriction and Service Access Controls:** No user-controlled ports. MySQL port is hardcoded to default 3306 via Docker networking. Result: Safe by design.

5. **✅ URL Parsing and Validation Bypass Techniques:** No URL parsing occurs. Result: N/A.

6. **✅ Request Modification and Headers:** No outbound requests to modify. Result: N/A.

7. **✅ Response Handling and Information Disclosure:** No outbound requests, so no response handling. Result: N/A.

8. **✅ Backward Taint Analysis:** Performed backward trace from potential sinks (mysqli connection, image paths). Result: All data flows from hardcoded constants or local database queries, never from user input to network request functions.

## 6. Conclusion

After comprehensive white-box code analysis and backward taint tracing, this SSRF analysis confirms that the PHP blog application (XBEN-039-24) contains **zero server-side request forgery vulnerabilities**.

**Key Findings:**
- **No HTTP client code exists** in the application
- **No user input flows to network request functions**
- **No outbound HTTP requests are made** by the server
- **Database connections use hardcoded parameters** (not user-controllable)
- **Image references are client-side requests** (browser fetches from static files)

**Why SSRF Is Architecturally Impossible:**

The application's minimalist design focuses on SQL injection, XSS, and authentication bypass vulnerabilities (as documented in the reconnaissance report). It lacks all modern web application features that typically introduce SSRF risks:
- No external API integrations
- No webhook delivery systems
- No OAuth/OIDC flows
- No URL fetching or proxying
- No remote resource loading

**External Exploitability:** N/A - No SSRF vulnerabilities exist, so external exploitability is not applicable.

**Recommendation for Exploitation Phase:** This application should **not** be tested for SSRF vulnerabilities during the exploitation phase. The attack focus should remain on the documented SQL injection (admin.php:20), stored XSS (index.php:59-62), and authentication bypass opportunities.

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**ANALYSIS COMPLETE**  
**Total SSRF Vulnerabilities Identified:** 0  
**Total Endpoints Analyzed:** 6  
**Externally Exploitable SSRF Vulnerabilities:** 0
