# SSRF Analysis Report

## 1. Executive Summary

- **Analysis Status:** Complete
- **Key Outcome:** After comprehensive analysis of the PHP blog application, **NO Server-Side Request Forgery (SSRF) vulnerabilities were identified**. The application does not make any outbound HTTP requests, does not process URLs from user input, and does not integrate with external services.
- **Purpose of this Document:** This report provides strategic context on the application's network architecture, confirms the absence of outbound request mechanisms, and documents why SSRF vulnerabilities are not applicable to this application.

## 2. Application Network Architecture

### 2.1 Technology Stack
- **Frontend:** Plain HTML5 with minimal CSS (styles.css)
- **Backend:** PHP 7.4.33 (EOL) with Apache 2.4.54
- **Database:** MySQL 5.7 (internal Docker network)
- **Infrastructure:** Docker Compose with two-container architecture

### 2.2 Network Communication Flow
The application's network communication is strictly limited:

```
User Browser
     ↓ HTTP (Port 80/443)
[Caddy Reverse Proxy]
     ↓ HTTP (Port 80)
[Web Container - PHP/Apache]
     ↓ MySQL Protocol (Port 3306, Internal Docker Network Only)
[Database Container - MySQL 5.7]
```

**Critical Observation:** The **only network communication** the application makes is from the web container to the MySQL database container over the internal Docker network. There are **ZERO outbound connections** to external networks, services, or URLs.

### 2.3 Application Components
The application consists of only two PHP files:
- **index.php** (72 lines): Blog homepage with category filtering
- **admin.php** (59 lines): Authentication page displaying CTF flag

Total functional code: 131 lines of PHP

## 3. SSRF Vulnerability Analysis - Comprehensive Review

### 3.1 HTTP Client Library Analysis

**Finding:** NO HTTP client functionality detected in the codebase.

**Searched Functions/Libraries:**
- ✓ `curl_init`, `curl_exec`, `curl_setopt`, `curl_close` - **NOT FOUND**
- ✓ `file_get_contents` with URL wrappers (`http://`, `https://`) - **NOT FOUND**
- ✓ `fopen`, `fsockopen`, `pfsockopen` with URLs - **NOT FOUND**
- ✓ `stream_socket_client` - **NOT FOUND**
- ✓ `stream_context_create` for HTTP contexts - **NOT FOUND**
- ✓ Guzzle HTTP client library - **NOT FOUND**
- ✓ Any other third-party HTTP libraries - **NOT FOUND**

**Verification Method:** Manual code review of all PHP files, grep searches for HTTP client patterns
**Code Evidence:** No imports, no function calls, no HTTP client initialization in index.php or admin.php

**Conclusion:** The application has **zero capability** to make outbound HTTP/HTTPS requests.

### 3.2 Raw Sockets & Network Connection Analysis

**Finding:** NO raw socket operations detected.

**Searched Functions:**
- ✓ `socket_create`, `socket_connect`, `socket_bind` - **NOT FOUND**
- ✓ `fsockopen`, `pfsockopen` - **NOT FOUND**
- ✓ `stream_socket_client` - **NOT FOUND**

**Network Connections Found:**
- MySQLi database connection only (lines: index.php:2, admin.php:12)
  - Host: `'db'` (internal Docker hostname)
  - Protocol: MySQL native protocol (not HTTP)
  - Scope: Internal container network only

**Conclusion:** The application does not create or manipulate network sockets beyond MySQL database connections.

### 3.3 URL Processing & Remote File Inclusion

**Finding:** NO URL processing or remote file inclusion detected.

**File Inclusion Analysis:**
- **index.php:** No `include`, `require`, `include_once`, `require_once` statements
- **admin.php:** No file inclusion statements
- **No dynamic includes:** Application has no plugin system or dynamic code loading

**URL Input Analysis:**
- No GET/POST parameters accept URLs
- No validation functions for URLs (`filter_var($url, FILTER_VALIDATE_URL)`) - **NOT FOUND**
- No URL parsing (`parse_url()`) - **NOT FOUND**
- No URL scheme processing

**Image Reference Analysis:**
- **Location:** index.php, Line 60
- **Code:** `echo "<img src='images/{$row['image']}' alt='{$row['title']}'...";`
- **Type:** Client-side HTML rendering only
- **Risk Classification:** **NOT SSRF** - The browser fetches the image, not the server
- **Path Type:** Relative local path to static directory (`images/`)
- **User Control:** Limited to database values (SQL injection risk, not SSRF)

**Conclusion:** No server-side URL fetching or remote file inclusion exists.

### 3.4 Redirect & URL Navigation Handlers

**Finding:** NO server-side redirect functionality with user-controlled URLs.

**Redirect Analysis:**
- Searched for `header('Location: ')` - **NOT FOUND**
- Searched for `http_redirect()` - **NOT FOUND**
- Searched for JavaScript `window.location` - **NOT FOUND**
- Searched for META refresh redirects - **NOT FOUND**

**Code Evidence:**
- admin.php line 4 contains comment: `// Check if the user is already logged in and redirect to the protected page`
- **However:** No actual redirect code is implemented below this comment
- Form submissions use same-page submission (no redirect parameter)

**Conclusion:** No redirect-based SSRF vectors exist.

### 3.5 Webhook & Callback Mechanisms

**Finding:** NO webhook, callback, or notification functionality detected.

**Searched Functionality:**
- "Ping my webhook" features - **NOT FOUND**
- Outbound callback verification - **NOT FOUND**
- HTTP POST notifications - **NOT FOUND**
- Event delivery confirmations - **NOT FOUND**
- Health check notifications to external URLs - **NOT FOUND**

**Conclusion:** The application does not send any outbound notifications, webhooks, or callbacks.

### 3.6 Third-Party Service Integration

**Finding:** NO external API integrations or service calls detected.

**Searched Integration Patterns:**
- OAuth/OpenID Connect providers - **NOT FOUND**
- Payment gateway integrations - **NOT FOUND**
- Cloud storage APIs - **NOT FOUND**
- Email delivery services - **NOT FOUND**
- Analytics tracking - **NOT FOUND**
- CDN integrations - **NOT FOUND**

**Authentication:** Simple username/password stored in MySQL (no external identity providers)

**Conclusion:** The application is completely self-contained with no external dependencies.

### 3.7 Media Processing & URL Fetchers

**Finding:** NO media processing with remote URL support detected.

**Searched Technologies:**
- ImageMagick (`convert`, `identify`) - **NOT FOUND**
- FFmpeg - **NOT FOUND**
- PDF generators (wkhtmltopdf, puppeteer) - **NOT FOUND**
- Image optimization services - **NOT FOUND**

**Static Images:**
- Application serves two pre-existing static images: `morning-dew.jpg`, `sunset.jpg`
- No dynamic image processing or fetching from URLs

**Conclusion:** No media processing that could be exploited for SSRF.

### 3.8 Link Preview & URL Metadata Fetchers

**Finding:** NO link preview or URL unfurling functionality detected.

**Searched Functionality:**
- Open Graph metadata fetchers - **NOT FOUND**
- oEmbed endpoint fetchers - **NOT FOUND**
- Social media card generators - **NOT FOUND**
- URL preview thumbnails - **NOT FOUND**

**Conclusion:** No URL metadata fetching capabilities exist.

### 3.9 SSO/OIDC Discovery & JWKS Fetchers

**Finding:** NO federated authentication or JWKS functionality detected.

**Searched Functionality:**
- OpenID Connect discovery (`.well-known/openid-configuration`) - **NOT FOUND**
- JWKS (JSON Web Key Set) fetchers - **NOT FOUND**
- OAuth metadata endpoints - **NOT FOUND**
- SAML metadata fetchers - **NOT FOUND**

**Authentication Implementation:**
- Traditional username/password stored in MySQL
- No external identity providers
- No token validation requiring remote key fetching

**Conclusion:** No SSO/OIDC-related SSRF vectors exist.

### 3.10 Import & Data Loading Functionality

**Finding:** NO remote data import functionality detected.

**Searched Functionality:**
- "Import from URL" features - **NOT FOUND**
- CSV/JSON/XML remote loaders - **NOT FOUND**
- RSS/Atom feed readers - **NOT FOUND**
- API synchronization - **NOT FOUND**
- Configuration fetchers from URLs - **NOT FOUND**

**Data Sources:**
- All data seeded at deployment via `db_init.sql`
- No dynamic data import mechanisms

**Conclusion:** No import-based SSRF vectors exist.

### 3.11 XML Processing (XXE-based SSRF)

**Finding:** NO XML processing functionality detected.

**Searched Functions:**
- `simplexml_load_string`, `simplexml_load_file` - **NOT FOUND**
- `DOMDocument::load`, `DOMDocument::loadXML` - **NOT FOUND**
- `xml_parse` - **NOT FOUND**
- `XMLReader` - **NOT FOUND**

**Conclusion:** No XML processing that could enable XXE-based SSRF.

### 3.12 Command Injection Leading to SSRF

**Finding:** NO command execution functionality detected.

**Searched Functions:**
- `exec`, `shell_exec`, `system`, `passthru` - **NOT FOUND**
- `proc_open`, `popen` - **NOT FOUND**
- Backtick operators (`` `command` ``) - **NOT FOUND**

**Conclusion:** No command execution capability that could be leveraged for SSRF via tools like `curl` or `wget`.

### 3.13 Database-Triggered SSRF

**Finding:** NO database features that could trigger outbound requests.

**Database Analysis:**
- No `LOAD DATA INFILE` with URLs
- No MySQL UDF (User Defined Functions) making HTTP requests
- No stored procedures calling external services
- No database triggers with network operations

**Database Schema Review:**
- Tables: posts, comments, users (simple structure)
- No URL columns requiring validation
- No webhook_url or callback_url fields

**Conclusion:** Database operations cannot be exploited for SSRF.

### 3.14 Docker Health Checks

**Finding:** Health checks are **INBOUND**, not outbound (NOT SSRF).

**Health Check Configuration:**
- **Web Container:** `curl -f http://127.0.0.1:80/` (docker-compose.yml lines 18-19)
- **Database Container:** `mysqladmin ping --silent` (docker-compose.yml lines 32-33)

**Analysis:**
- Docker orchestration performs these checks against the container itself
- These are **INBOUND** checks (Docker → Container), not outbound requests
- No user input influences these checks
- They run in the Docker daemon, not in the application runtime

**Conclusion:** Health checks are NOT SSRF sinks.

## 4. Dominant Vulnerability Patterns

**Pattern Identified:** No SSRF vulnerability patterns exist in this application.

**Why SSRF is Not Applicable:**

1. **No HTTP Client Libraries:** The application does not import, initialize, or use any HTTP client libraries or functions.

2. **No URL Processing:** User input is never parsed as a URL, validated as a URL, or used to construct HTTP requests.

3. **Limited Functionality:** The application's core functionality is limited to database queries and HTML rendering.

4. **No External Integrations:** The application does not call APIs, fetch remote resources, or integrate with third-party services.

5. **Network Isolation:** The application only connects to MySQL on the internal Docker network.

6. **Static References Only:** All file references (images, CSS) are local static paths served by Apache.

## 5. Strategic Intelligence for Exploitation

**Network Architecture:**
- Application runs in isolated Docker containers
- Only exposed port: 80/443 (HTTP/HTTPS via Caddy reverse proxy)
- Database port 3306 is internal-only (not published to host)
- No outbound firewall rules needed (application never initiates external connections)

**HTTP Client Usage:** NONE

**Request-Making Endpoints:** NONE

**URL Parameter Endpoints:** NONE that accept URLs for server-side processing

**Internal Services Accessible:** N/A (no SSRF capability exists)

## 6. Secure by Design: Validated Components

The application's architecture is inherently secure against SSRF due to its minimal design:

| Component/Flow | Endpoint/File Location | Defense Mechanism Implemented | Verdict |
|---|---|---|---|
| Blog Homepage | `index.php` | No HTTP client functionality implemented | SAFE (No SSRF capability) |
| Admin Authentication | `admin.php` | No external service calls or URL processing | SAFE (No SSRF capability) |
| Image Rendering | `index.php:60` | Client-side HTML rendering only; no server-side URL fetching | SAFE (Not an SSRF sink) |
| Database Connections | `index.php:2, admin.php:12` | Internal Docker network only (vpc-only isolation) | SAFE (Internal communication) |
| Static Resources | `/images/*`, `/styles.css` | Served by Apache; no dynamic URL fetching | SAFE (No SSRF capability) |

## 7. Vulnerabilities Identified in Other Categories

While no SSRF vulnerabilities exist, the application has critical security issues:

**SQL Injection:**
- **Location:** index.php line 45 (category parameter)
- **Risk:** CRITICAL - Complete database compromise
- **Reference:** See SQL Injection analysis deliverable

**Stored XSS:**
- **Location:** index.php lines 58-61 (database content rendering)
- **Risk:** HIGH - JavaScript injection via poisoned database
- **Reference:** See XSS analysis deliverable

**Authentication Weaknesses:**
- Plaintext password storage
- No session regeneration (session fixation risk)
- No HTTPS enforcement

## 8. Conclusion

**SSRF VULNERABILITY STATUS: NOT PRESENT**

After systematic analysis of all potential SSRF vectors according to the white-box methodology, **ZERO SSRF vulnerabilities were identified** in this application.

**Justification:**

1. ✓ No HTTP client libraries or functions exist
2. ✓ No URL processing from user input
3. ✓ No outbound network requests (except internal MySQL)
4. ✓ No redirect handlers with user-controlled URLs
5. ✓ No webhook or callback mechanisms
6. ✓ No external service integrations
7. ✓ No media processors fetching remote URLs
8. ✓ No import/data loading from URLs
9. ✓ No XML processing (XXE vectors)
10. ✓ No command execution capability
11. ✓ No database-triggered outbound requests
12. ✓ No SSO/OIDC/JWKS fetchers

**The application's network communication model is strictly unidirectional:**
- **Inbound:** User → Web Server → MySQL Database
- **Outbound:** NONE (no external requests initiated by application)

**External Attacker Perspective:**
From an external attacker with access to http://localhost:34389, there is **no attack surface** for SSRF exploitation because the application lacks any mechanism to make outbound HTTP requests or process user-supplied URLs.

**Recommendation:**
The SSRF Exploitation phase can be **SKIPPED** for this application. Resources should be focused on exploiting the identified SQL injection and XSS vulnerabilities instead.

---

**Analysis completed by:** SSRF Analysis Specialist  
**Date:** 2025-01-XX  
**Application:** XBEN-078-24 (PHP Blog CTF Challenge)  
**Total Endpoints Analyzed:** 3 functional endpoints (index.php, admin.php GET/POST)  
**SSRF Sinks Identified:** 0  
**Exploitation Queue Status:** Empty (no vulnerabilities to exploit)
