# SSRF Analysis Report

## 1. Executive Summary
- **Analysis Status:** Complete
- **Key Outcome:** No Server-Side Request Forgery (SSRF) vulnerabilities were identified in the PayBuddies Portal application. After comprehensive analysis of all network-accessible endpoints, no code paths were found that make server-side HTTP requests based on user input or otherwise.
- **Purpose of this Document:** This report provides a comprehensive analysis of the application's request-making capabilities and confirms the complete absence of SSRF attack surface. While the application has critical vulnerabilities in other areas (SQL injection, arbitrary file upload, path traversal), SSRF exploitation is definitively not possible.

## 2. Dominant Vulnerability Patterns

### Pattern 1: Complete Absence of HTTP Client Functionality
- **Description:** The PayBuddies Portal application is a minimalist PHP application with no HTTP client libraries, no URL fetching capabilities, and no server-side request functionality. The application performs only three core functions: user authentication via local MySQL, file upload to local storage, and session management.
- **Implication:** Without any mechanism to make outbound HTTP requests, SSRF attacks are impossible regardless of user input control. The application lacks curl, file_get_contents with URLs, socket connections, and all other common SSRF vectors.
- **Representative Findings:** Comprehensive search across all 4 PHP files revealed zero instances of curl_init, file_get_contents, fsockopen, or any other network request functions.

### Pattern 2: Hardcoded Redirects Only
- **Description:** All three redirect statements in the application use hardcoded static URLs with no user input influence. The redirects serve only for internal navigation between login page and dashboard.
- **Implication:** Open redirect attacks (a common SSRF precursor) are not possible. No user-controllable parameters influence redirect destinations.
- **Representative Finding:** All `header("Location:")` calls use literal strings: "dashboard.php" and "index.php?error=failed_login"

### Pattern 3: Local-Only File Operations
- **Description:** The file upload functionality stores uploaded files to local filesystem using move_uploaded_file() without any content processing, URL extraction, or network operations.
- **Implication:** While the upload feature has critical path traversal and arbitrary file upload vulnerabilities, it cannot be leveraged for SSRF as files are never parsed, processed, or used to trigger network requests.
- **Representative Finding:** upload.php line 39 uses only move_uploaded_file() - a purely local filesystem operation with no network capability.

## 3. Strategic Intelligence for Exploitation

**HTTP Client Library:** NONE - The application uses no HTTP client libraries. No composer.json exists, and no PHP HTTP request functions are invoked.

**Request Architecture:** The application makes NO outbound HTTP requests. Its network operations are limited to:
- Incoming HTTP requests from users (Apache handles this)
- Local MySQL connections over localhost socket
- Session file writes to local filesystem

**Internal Services:** 
- MySQL 8.0 on localhost (accessed via MySQLi, not HTTP)
- Apache 2.4 web server (serves incoming requests only)
- Supervisord process manager (local process management)
- No internal HTTP-based microservices
- No message queues or async job processors
- No webhook handlers or callback mechanisms

**Application Capabilities:**
1. User authentication (username/password against local MySQL database)
2. File upload to `./uploaded_invoices/` directory (local storage only)
3. Session management (PHP native sessions on local filesystem)

**Application Does NOT:**
- Make HTTP/HTTPS requests to any destination
- Fetch URLs or remote resources
- Process URLs from user input
- Use curl, wget, or any HTTP client
- Parse file content for embedded URLs
- Connect to external APIs or services
- Implement webhooks or callbacks
- Use XML with external entities
- Process images with remote resource loading

**Network-Accessible Endpoints (Complete Inventory):**
1. `GET/POST /index.php` - Login page and authentication API
2. `GET /dashboard.php` - Upload form display (requires authentication)
3. `POST /upload.php` - File upload handler (requires authentication)
4. `GET /uploaded_invoices/{filename}` - Direct file access via Apache (no PHP processing)

**Missing Functionality (Common SSRF Vectors):**
- No URL preview or metadata extraction
- No "import from URL" features
- No image/PDF processing with external resource loading
- No SSO/OIDC/OAuth with remote discovery
- No webhook testing or callback verification
- No monitoring or health check endpoints that ping external URLs
- No API proxy or forwarding functionality

## 4. Secure by Design: Validated Components

These components were analyzed and found to have no SSRF attack surface due to complete absence of server-side request functionality. They are documented here as evidence of thorough analysis.

| Component/Flow | Endpoint/File Location | Defense Mechanism Implemented | Verdict |
|---|---|---|---|
| Authentication System | `/app/website/index.php` lines 19-53 | No HTTP clients used; only local MySQL queries for credential verification. No URL parameters processed. | SAFE (No SSRF vectors) |
| File Upload Handler | `/app/website/upload.php` lines 19-46 | Files processed with move_uploaded_file() only - purely local operation. No content parsing, no URL extraction, no network requests triggered. | SAFE (No SSRF vectors) |
| Session Management | All PHP files (session_start() calls) | Uses PHP native file-based sessions stored on local filesystem. No remote session storage or synchronization. | SAFE (No SSRF vectors) |
| Redirect Handlers | `index.php:11`, `dashboard.php:14`, `upload.php:14` | All redirect destinations are hardcoded static strings. No user input influences Location headers. | SAFE (No open redirect or SSRF) |
| Database Configuration | `/app/website/include/db_config.php` | Uses mysqli_connect() to localhost MySQL. Connection is local-only with no HTTP-based database access. | SAFE (No SSRF vectors) |
| Static Asset References | All PHP files (CDN links in HTML) | External CDN resources (Bootstrap, jQuery, Font Awesome) are loaded client-side by browsers, not server-side. No server-side fetching of these resources. | SAFE (Client-side loading only) |

## 5. Analysis Methodology Applied

The following systematic checks were performed according to the SSRF analysis methodology:

### 1) HTTP Client Usage Patterns - NONE FOUND
- **Endpoints Analyzed:** All 4 PHP files (index.php, dashboard.php, upload.php, db_config.php)
- **Functions Searched:** curl_init, curl_exec, curl_setopt, file_get_contents, fopen, readfile, copy, stream_get_contents
- **Result:** Zero instances found
- **Conclusion:** Application has no capability to make HTTP requests

### 2) Protocol and Scheme Validation - NOT APPLICABLE
- **Reason:** No endpoints accept URL parameters or process URLs
- **Parameters Analyzed:** $_POST['username'], $_POST['password'], $_GET['error'], $_FILES['invoice']
- **Result:** None of these parameters are used in URL construction or network operations
- **Conclusion:** No protocol validation needed as no URLs are processed

### 3) Hostname and IP Address Validation - NOT APPLICABLE
- **Reason:** No URL parameters exist to validate
- **Search Results:** No parameters named "url", "callback", "webhook", "redirect", "target", "site", "link", "dest", "return_to", "next", or similar
- **Conclusion:** No hostname validation needed

### 4) Port Restriction and Service Access Controls - NOT APPLICABLE
- **Reason:** Application makes no network connections to variable destinations
- **Fixed Connections:** Only connects to localhost:3306 (MySQL) with hardcoded credentials
- **Conclusion:** No port restriction validation needed as no user-controllable connections exist

### 5) URL Parsing and Validation Bypass - NOT APPLICABLE
- **Reason:** No URL parsing functions are invoked
- **Filename Analysis:** While filenames are user-controlled in upload.php, they are treated as literal filesystem paths, not parsed as URLs
- **Test Result:** Filename "http://example.com/test.pdf" would create file literally named that, not fetch the URL
- **Conclusion:** No URL parsing to bypass

### 6) Request Modification and Headers - NOT APPLICABLE
- **Reason:** No outbound requests exist to modify
- **Header Searches:** Searched for curl_setopt (for custom headers) - not found
- **Conclusion:** No request modification possible

### 7) Response Handling and Information Disclosure - NOT APPLICABLE
- **Reason:** No responses from external servers to handle
- **Output Analysis:** All echo statements output static strings or database results, never HTTP response content
- **Conclusion:** No external response handling exists

## 6. Backward Taint Analysis Results

**SSRF Sinks from Pre-Recon (Section 10):** ZERO sinks identified

Since no SSRF sinks were discovered in the pre-recon phase, no backward taint analysis was required. However, for completeness, the following analysis was performed:

### Potential Sink Candidates Analyzed:

**Candidate 1: File Upload Filename**
- **Location:** `/app/website/upload.php` line 22
- **Variable:** `$fileName = $_FILES['invoice']['name'];`
- **Sink:** Line 33: `$dest_path = $uploadFileDir . $fileName;`
- **Trace Backward:** User upload → $_FILES['invoice']['name'] → $fileName → concatenated with $uploadFileDir → used in move_uploaded_file()
- **Sanitization:** NONE (path traversal vulnerability)
- **Network Activity:** NONE - move_uploaded_file() is filesystem-only operation
- **Verdict:** NOT an SSRF sink (path traversal vulnerability instead)

**Candidate 2: GET Error Parameter**
- **Location:** `/app/website/index.php` line 15
- **Variable:** `$_GET['error']`
- **Sink:** Checked for existence, value assigned to hardcoded "failed_login"
- **Trace Backward:** User input → $_GET['error'] → isset() check → hardcoded assignment
- **Usage:** Only controls whether error div is displayed
- **Network Activity:** NONE
- **Verdict:** NOT an SSRF sink

**Candidate 3: POST Username Parameter**
- **Location:** `/app/website/index.php` line 21
- **Variable:** `$realusername = $_POST['username'];`
- **Sink:** Line 25: SQL query - `"SELECT username FROM users WHERE username = '$realusername'"`
- **Trace Backward:** User input → $_POST['username'] → $realusername → SQL query
- **Network Activity:** NONE - mysqli_query operates on local MySQL connection
- **Verdict:** SQL injection sink, NOT SSRF sink

**Candidate 4: Redirect Destinations**
- **Locations:** index.php:11, dashboard.php:14, upload.php:14
- **Trace Backward:** All redirect URLs are hardcoded strings with no variables
- **User Input Influence:** NONE
- **Verdict:** NOT SSRF sinks (no user control)

### Conclusion of Taint Analysis:
NO backward traces led to server-side HTTP request functions because no such functions exist in the codebase.

## 7. Comprehensive Search Results

### Functions Searched and Results:

**HTTP Clients:**
- `curl_init()` - 0 matches
- `curl_exec()` - 0 matches
- `curl_setopt()` - 0 matches
- `curl_multi_*()` - 0 matches
- `file_get_contents()` - 0 matches
- `fopen()` - 0 matches

**Socket Functions:**
- `fsockopen()` - 0 matches
- `pfsockopen()` - 0 matches
- `socket_connect()` - 0 matches
- `stream_socket_client()` - 0 matches

**URL Fetching:**
- `readfile()` - 0 matches
- `copy()` with URLs - 0 matches
- `stream_get_contents()` - 0 matches
- `stream_context_create()` - 0 matches

**XML/SOAP:**
- `simplexml_load_file()` - 0 matches
- `DOMDocument::load()` - 0 matches
- `SoapClient` - 0 matches
- `XMLReader` - 0 matches

**Image Processing:**
- `getimagesize()` - 0 matches
- `imagecreatefrom*()` - 0 matches
- `exif_read_data()` - 0 matches
- ImageMagick functions - 0 matches

**Common SSRF Parameter Names:**
- "url" parameter - 0 matches (except in hardcoded CDN URLs)
- "callback" parameter - 0 matches
- "webhook" parameter - 0 matches
- "redirect" parameter - 0 matches
- "next" parameter - 0 matches
- "return_to" parameter - 0 matches

### Files Analyzed (Complete List):
1. `/app/website/index.php` (194 lines) - Authentication logic
2. `/app/website/dashboard.php` (84 lines) - Upload form
3. `/app/website/upload.php` (56 lines) - File upload handler
4. `/app/website/include/db_config.php` (9 lines) - Database config

**Total Lines Analyzed:** 343 lines of PHP code
**SSRF Sinks Found:** 0

## 8. Edge Cases and Uncommon Vectors Analyzed

### Edge Case 1: Indirect SSRF via SQL Injection
**Hypothesis:** Could SQL injection be used to trigger MySQL-based SSRF (e.g., LOAD DATA INFILE)?
**Analysis:** 
- SQL injection exists in index.php lines 25 and 35
- MySQL database user has ALL PRIVILEGES (excessive)
- MySQL 8.0 running on localhost
**Test:** Could attacker inject `SELECT LOAD_FILE('http://attacker.com/file')`?
**Result:** MySQL LOAD_FILE() requires `file://` not `http://`. Would need UNC paths on Windows or file:// on Linux. Current container is Linux, and LOAD_FILE would only access local filesystem.
**Verdict:** NOT a viable SSRF vector (though SQL injection is still critical)

### Edge Case 2: SSRF via File Upload with SVG XXE
**Hypothesis:** Upload SVG with external entity pointing to internal service
**Analysis:**
- Application accepts file uploads but never parses them
- No XML processing libraries used
- Files stored but never opened or processed
**Test:** Upload SVG with `<!ENTITY xxe SYSTEM "http://localhost:22">`
**Result:** File would be stored but never parsed. No XML parser invoked.
**Verdict:** NOT an SSRF vector

### Edge Case 3: SSRF via Redirect Following
**Hypothesis:** Manipulate redirect to force server to fetch URLs
**Analysis:**
- All redirects are HTTP 302/301 Location headers sent to client
- Client browser follows redirects, not server
- No server-side redirect following (no curl with CURLOPT_FOLLOWLOCATION)
**Verdict:** NOT an SSRF vector

### Edge Case 4: SSRF via DNS Rebinding
**Hypothesis:** Use DNS rebinding to bypass localhost restrictions
**Analysis:**
- Application doesn't make HTTP requests, so DNS resolution irrelevant
- MySQL connection uses hardcoded "localhost", not user input
**Verdict:** NOT applicable (no HTTP requests to rebind)

### Edge Case 5: Blind SSRF via Error Messages
**Hypothesis:** Trigger timing differences based on unreachable hosts
**Analysis:**
- No network functions that could timeout differently
- All operations are local (database, filesystem, session)
**Verdict:** NOT possible (no network operations)

## 9. Other Vulnerabilities Identified (Not SSRF)

While performing SSRF analysis, the following CRITICAL vulnerabilities were identified:

### 1. SQL Injection (CRITICAL)
**Location:** `/app/website/index.php` lines 25, 35
**Description:** Username and password parameters directly concatenated into SQL queries without sanitization
**Impact:** Authentication bypass, database compromise
**Proof of Concept:** `username=admin' OR '1'='1' --`
**SSRF Relation:** None - this is a separate vulnerability class

### 2. Path Traversal (CRITICAL)
**Location:** `/app/website/upload.php` line 33
**Description:** User-supplied filename used without sanitization in filesystem path
**Impact:** Arbitrary file write, potential remote code execution
**Proof of Concept:** Upload file named `../../index.php.pdf`
**SSRF Relation:** None - filesystem vulnerability, not network

### 3. Arbitrary File Upload (HIGH)
**Location:** `/app/website/upload.php` line 30
**Description:** Weak validation using strpos() allows bypasses like `shell.php.pdf`
**Impact:** Remote code execution via uploaded webshell
**SSRF Relation:** None - local code execution vulnerability

## 10. Recommendations

### For Exploitation Team:
Since NO SSRF vulnerabilities exist, the exploitation team should focus on:
1. **SQL Injection** for authentication bypass and data exfiltration
2. **Path Traversal + Arbitrary File Upload** for remote code execution
3. Session hijacking and session fixation attacks
4. Brute force attacks (no rate limiting)

### For Defensive Hardening (If This Were Production):
While SSRF is not a concern for this application, the following would improve security posture:
1. Implement prepared statements for all database queries
2. Sanitize filenames with basename() and validate with allowlists
3. Implement proper file content validation (magic bytes, MIME type)
4. Add CSRF protection to all forms
5. Enable session security flags (HttpOnly, Secure, SameSite)
6. Implement rate limiting on authentication endpoints

### If SSRF Testing is Required:
To create SSRF test opportunities, the application would need features such as:
- "Fetch invoice from URL" functionality
- Webhook callback testing
- Image processing from external URLs
- API integrations with user-supplied endpoints
- URL preview or metadata extraction

## 11. Conclusion

After exhaustive analysis using systematic methodology, backward taint analysis, and comprehensive code review, **NO SSRF vulnerabilities exist in the PayBuddies Portal application**.

**Confidence Level:** HIGH

The application's minimalist architecture with only 343 lines of PHP code, absence of HTTP client libraries, absence of URL-processing functionality, and complete lack of server-side request mechanisms makes SSRF exploitation impossible.

**Final Verdict:** 
- **SSRF Risk:** NONE
- **Externally Exploitable SSRF:** 0 vulnerabilities
- **Exploitation Queue:** Empty (no SSRF findings to pass to exploitation phase)

This analysis confirms that penetration testing resources should be allocated to the confirmed SQL injection and file upload vulnerabilities rather than attempting SSRF exploitation.