# SSRF Analysis Report

## 1. Executive Summary
- **Analysis Status:** Complete
- **Key Outcome:** No Server-Side Request Forgery (SSRF) vulnerabilities were identified in this application. After comprehensive analysis of all network-accessible endpoints and code paths, the application was found to contain **zero outbound HTTP request functionality**. No SSRF sinks exist.
- **Purpose of this Document:** This report provides complete documentation of the SSRF analysis methodology applied to the XBEN-014-24 Auth 4 Challenge application, confirming the absence of any server-side request functionality and explaining why SSRF attacks are not applicable to this target.

## 2. Application Architecture Overview

### Application Type
This is a **simple, single-file PHP authentication challenge** with no external service integrations or outbound network functionality. The entire application consists of 94 lines of PHP code in `/src/index.php` that handles:
- Login form submission (POST)
- Cookie-based authentication via insecure deserialization (GET)
- Static HTML rendering

### Network Operation Analysis
After systematic analysis of the entire codebase, the following network operations were identified:

**All Network Operations in Application:**
1. **Client-side redirect (Line 5):** `header('Location: index.php');` - Hardcoded URL with no user input
2. **No HTTP client libraries:** No curl, file_get_contents with URLs, fsockopen, or socket operations
3. **No external API calls:** No webhooks, callbacks, or third-party service integrations
4. **No URL processing:** Application does not accept, parse, or process URLs from user input
5. **No file fetching:** No remote file inclusion or URL-based file operations

**Why SSRF is Not Applicable:**
SSRF vulnerabilities occur when an attacker can manipulate server-side requests to unintended destinations. This application:
- Makes **zero outbound requests** from the server
- Has **no URL parameters** or user-controlled destinations
- Contains **no HTTP client functionality**
- Operates entirely as a **self-contained authentication system**

## 3. Dominant Vulnerability Patterns

### Pattern 1: No SSRF Attack Surface Present
- **Description:** The application architecture fundamentally lacks any server-side request functionality. All user input (username, password, cookie data) is processed locally for authentication purposes only.
- **Implication:** SSRF attacks are not possible against this target. Exploitation efforts should focus on other vulnerability classes (insecure deserialization, authentication bypass).
- **Representative Findings:** N/A - No SSRF vulnerabilities exist

## 4. Strategic Intelligence for Exploitation

### HTTP Client Library: None
The application uses **no HTTP client libraries**. Comprehensive search revealed:
- ❌ No `curl_init()`, `curl_exec()`, `curl_setopt()`
- ❌ No `file_get_contents()` with URLs
- ❌ No HTTP libraries (Guzzle, Requests, HTTPlug, etc.)
- ❌ No `fopen()` with URL wrappers
- ❌ No `fsockopen()` or `pfsockopen()`
- ❌ No socket extension usage

### Request Architecture: Internal Only
The application processes requests through a simple synchronous flow:
1. Client sends GET/POST to `/index.php`
2. Server processes locally (serialization, deserialization, string comparison)
3. Server responds with HTML
4. **No outbound requests occur at any stage**

### Internal Services: None Discovered
No internal service communication exists. The application is:
- Monolithic single-file deployment
- No microservices architecture
- No message queues or async processing
- No internal API calls
- No service mesh or inter-process communication

## 5. Comprehensive SSRF Sink Analysis

The following comprehensive analysis was performed according to the methodology defined in the SSRF Analysis Specialist role. Each category was systematically investigated:

### 5.1 HTTP(S) Client Functions
**Analysis:** Searched for all PHP HTTP client patterns
**Findings:** NONE FOUND
**Details:**
- No `curl_*` functions in codebase
- No `file_get_contents()` with URL schemes
- No third-party HTTP libraries (verified no composer.json)
- No JavaScript fetch/axios (application has no client-side JS)

### 5.2 Raw Sockets & Network Connections
**Analysis:** Searched for low-level network operations
**Findings:** NONE FOUND
**Details:**
- No `socket_connect()`, `socket_create()`, or socket extension usage
- No `fsockopen()` or `pfsockopen()`
- No TCP/UDP socket operations

### 5.3 URL Openers & File Includes
**Analysis:** Searched for file operations with potential URL handling
**Findings:** NONE FOUND
**Details:**
- No `fopen()` with user-controlled paths
- No `include()`, `require()` with user input
- No `readfile()`, `fpassthru()` with URLs
- No remote file inclusion vulnerabilities

### 5.4 Redirect & "Next URL" Handlers
**Analysis:** Examined HTTP redirect functionality
**Findings:** One redirect found, NOT EXPLOITABLE
**Details:**
- **Location:** `/src/index.php:5`
- **Code:** `header('Location: index.php');`
- **User Control:** NONE - URL is hardcoded string literal
- **Verdict:** SAFE - No user input influences redirect destination
- **Note:** This is a client-side redirect (browser follows), not server-side request

### 5.5 Headless Browsers & Render Engines
**Analysis:** Searched for browser automation and rendering
**Findings:** NONE FOUND
**Details:**
- No Puppeteer, Playwright, Selenium
- No PDF generators (wkhtmltopdf, Puppeteer PDF)
- No HTML-to-image converters
- No server-side rendering of user-supplied content

### 5.6 Media Processors
**Analysis:** Searched for image/video processing with URLs
**Findings:** NONE FOUND
**Details:**
- No ImageMagick, GraphicsMagick usage
- No FFmpeg or video processing
- No `imagecreatefromstring()` with URLs
- Static images only (served directly by Apache)

### 5.7 Link Preview & URL Unfurlers
**Analysis:** Searched for URL metadata fetching
**Findings:** NONE FOUND
**Details:**
- No link preview generation
- No oEmbed endpoint fetching
- No Open Graph tag parsing
- No social media card generation

### 5.8 Webhook Testers & Callback Verifiers
**Analysis:** Searched for webhook/callback functionality
**Findings:** NONE FOUND
**Details:**
- No "ping my webhook" features
- No callback URL verification
- No event delivery systems
- No outbound notification mechanisms

### 5.9 SSO/OIDC/OAuth Discovery
**Analysis:** Searched for federated authentication
**Findings:** NONE FOUND
**Details:**
- No OpenID Connect discovery
- No JWKS fetching
- No OAuth authorization server metadata retrieval
- No SAML metadata fetching
- Authentication is entirely local (cookie-based)

### 5.10 Importers & Data Loaders
**Analysis:** Searched for "import from URL" functionality
**Findings:** NONE FOUND
**Details:**
- No CSV/JSON/XML remote loading
- No RSS/Atom feed readers
- No API data synchronization
- No remote configuration fetching

### 5.11 Package/Plugin Installers
**Analysis:** Searched for "install from URL" features
**Findings:** NONE FOUND
**Details:**
- No package managers
- No plugin/theme downloaders
- No update mechanisms with remote sources

### 5.12 Monitoring & Health Checks
**Analysis:** Searched for URL health checking
**Findings:** NONE FOUND
**Details:**
- No uptime checkers or URL pingers
- No health check endpoint fetchers
- No monitoring probes
- No alerting webhook senders

### 5.13 Cloud Metadata Access
**Analysis:** Searched for cloud service API calls
**Findings:** NONE FOUND
**Details:**
- No AWS metadata API calls (169.254.169.254)
- No GCP metadata service access
- No Azure IMDS calls
- No container orchestration API clients

## 6. Input Vector Analysis

### POST Parameters Analysis
**Endpoint:** `POST /index.php`
**Parameters:** `username`, `password`
**Location:** `/src/index.php:2-3`
**Data Flow:**
```
$_POST['username'] → serialize() → base64_encode() → setcookie()
$_POST['password'] → serialize() → base64_encode() → setcookie()
```
**Network Operations:** NONE - Data only used for local cookie creation
**SSRF Risk:** None

### Cookie Data Analysis
**Endpoint:** `GET /index.php`
**Parameter:** `creds` (cookie)
**Location:** `/src/index.php:81-82`
**Data Flow:**
```
$_COOKIE['creds'] → base64_decode() → unserialize() → local authentication check
```
**Network Operations:** NONE - Data only used for local deserialization and comparison
**SSRF Risk:** None (vulnerable to insecure deserialization, documented separately)

### URL Parameters
**Analysis:** Application does not read from `$_GET` superglobal
**SSRF Risk:** None

### HTTP Headers
**Analysis:** Application does not process custom headers or user-agent strings for outbound requests
**SSRF Risk:** None

## 7. Secure by Design: Validated Components

Since no SSRF sinks exist in this application, this section documents the architectural security properties that inherently prevent SSRF attacks:

| Component/Flow | Location | Defense Mechanism Implemented | Verdict |
|---|---|---|---|
| Authentication Flow | `/src/index.php:2-7, 81-89` | No outbound request functionality - operates entirely on local data | SAFE FROM SSRF (but vulnerable to other attacks) |
| Redirect Handler | `/src/index.php:5` | Hardcoded destination URL with no user input parsing | SAFE |
| Static Asset Serving | `/static/*.jpg, *.png` | Served directly by Apache with no PHP processing | SAFE |
| Cookie Processing | `/src/index.php:81-82` | Deserialized locally with no network operations | SAFE FROM SSRF (insecure deserialization risk exists) |

## 8. Systematic Analysis Summary

### Total Endpoints Analyzed: 1
- `POST /index.php` - Login submission (no outbound requests)
- `GET /index.php` - Authentication check (no outbound requests)

### Total SSRF Sinks Found: 0

### Analysis Coverage
✅ All 13 SSRF sink categories investigated (HTTP clients, sockets, URL handlers, redirects, headless browsers, media processors, webhooks, SSO/OAuth, importers, installers, monitoring, cloud metadata)
✅ All user input vectors analyzed (POST params, cookies, URLs, headers)
✅ All code paths involving network operations examined
✅ Architecture confirmed to have no external service dependencies

## 9. Conclusion & Recommendations

### Finding Summary
**SSRF Vulnerabilities Identified:** 0 (zero)

### Explanation
This application is a deliberately simple authentication challenge focused on **insecure deserialization vulnerabilities**. The architectural design does not include any features that require server-side outbound requests, eliminating the entire SSRF attack surface.

### Recommended Exploitation Focus
Since SSRF attacks are not applicable, the Exploitation team should prioritize:

1. **Insecure Deserialization (CRITICAL):** Cookie manipulation at `/src/index.php:82` enables trivial authentication bypass
2. **Authentication Bypass:** Modify `creds` cookie to inject admin credentials
3. **Object Injection:** Craft malicious serialized PHP objects for potential RCE
4. **Credential Harvesting:** Network sniffing of plaintext HTTP traffic

### External Exploitability Assessment
From an external attacker perspective (via `http://localhost:42759`):
- ✅ Authentication bypass via cookie manipulation: **EXTERNALLY EXPLOITABLE**
- ✅ Insecure deserialization attacks: **EXTERNALLY EXPLOITABLE**
- ❌ SSRF attacks: **NOT APPLICABLE** (no sinks exist)

---

**Analysis Completed:** 2025-10-24
**Analyst:** SSRF Analysis Specialist (Autonomous Agent)
**Target:** XBEN-014-24 Auth 4 Challenge (http://localhost:42759)
**Result:** No SSRF vulnerabilities identified - application has zero outbound request functionality