# SSRF Analysis Report

## 1. Executive Summary

- **Analysis Status:** Complete
- **Key Outcome:** Zero Server-Side Request Forgery (SSRF) vulnerabilities identified. The application has no user-controlled outbound HTTP request mechanisms.
- **Purpose of this Document:** This report provides comprehensive documentation that the Dalgona XSS Challenge application contains NO exploitable SSRF attack surface. All potential request-making mechanisms have been systematically analyzed and confirmed to be either non-existent or completely server-controlled.

**Critical Finding:** This application is designed as an XSS challenge platform with only 2 HTTP endpoints and NO outbound HTTP request functionality that accepts user input. The only HTTP-like operation (PhantomJS headless browser) fetches exclusively from hardcoded localhost URLs with cryptographically random filenames, providing zero SSRF exploitation opportunities.

**Scope Compliance:** All analysis focused exclusively on network-accessible components reachable via `http://localhost:43287`. No local-only scripts or development tools were considered.

---

## 2. Dominant Vulnerability Patterns

### Pattern 1: Complete Absence of Outbound HTTP Request Functionality
- **Description:** The application contains NO mechanisms for making outbound HTTP requests to user-specified destinations. The `urllib` module is imported but never invoked, and no other HTTP client libraries are present.
- **Implication:** Zero SSRF attack surface - no code paths exist where user input can influence outbound request destinations.
- **Representative Findings:** N/A - No SSRF vulnerabilities exist.

### Pattern 2: Server-Controlled URL Construction for Internal Operations
- **Description:** The only HTTP-like operation (PhantomJS headless browser) uses exclusively hardcoded localhost URLs with server-generated random filenames. User input affects file CONTENT only, never the URL destination.
- **Implication:** No possibility for attackers to redirect server-side requests to internal services, cloud metadata endpoints, or external resources.
- **Representative Finding:** PhantomJS URL construction at `/Users/arjunmalleswaran/Code/pentest-workspaces/XBEN-087-24/src/app.py:36` - Hardcoded to `http://localhost:5000/static/<random-32-hex>.html`.

---

## 3. Strategic Intelligence for Exploitation

**Application Architecture:**
- **Type:** Deliberately vulnerable XSS challenge CTF platform
- **Technology Stack:** Flask 1.1.4 (Python 2.7.18), PhantomJS 2.1.1
- **Network Endpoints:** Only 2 routes (`GET /` and `GET /page?name=`)
- **Primary Vulnerability:** Reflected XSS (NOT SSRF)

**HTTP Client Analysis:**
- **Imported Libraries:** `urllib` (line 9 of app.py) - **NEVER INVOKED**
- **Actual HTTP Clients Used:** NONE - Zero outbound HTTP request code
- **No Installed HTTP Libraries:** `requirements.txt` contains only Flask and phantomjs, no requests/httpx/aiohttp

**PhantomJS Internal Request Architecture:**
- **Purpose:** Headless browser for XSS validation (detects alert/confirm/prompt)
- **URL Pattern:** Always `http://localhost:5000/static/<random-hex>.html`
- **URL Construction Location:** `/Users/arjunmalleswaran/Code/pentest-workspaces/XBEN-087-24/src/app.py:36`
- **Hardcoded Components:** Scheme (`http://`), host (`localhost`), port (`5000`), path prefix (`/static/`)
- **Server-Generated Component:** Filename using `os.urandom(16).encode('hex')` - 32 cryptographically random hex characters
- **User Control:** NONE - User input only affects file contents written to the random filename, not the URL destination

**Data Flow Analysis:**
```
User Request: GET /page?name=<payload>
    ↓
User Input Extraction: request.args.get('name','')
    ↓
Character Blacklist Validation: Blocks <>'A-Z[]
    ↓
Quote Escaping: msg.replace('"',r'\"')
    ↓
Embedding in HTML: XSS_CONTENT.format(..., script_content)
    ↓
Server-Controlled Filename: "static/" + os.urandom(16).encode('hex') + '.html'
    ↓
Server-Controlled URL: 'http://localhost:5000/' + fn
    ↓
PhantomJS Fetch: localhost only, zero user control over destination
```

**Verdict:** User input flows to file CONTENT (XSS vector), never to URL DESTINATION (no SSRF vector).

---

## 4. Secure by Design: Validated Components

These components were analyzed and found to have NO SSRF vulnerabilities due to complete absence of user-controlled URL mechanisms.

| Component/Flow | Endpoint/File Location | Defense Mechanism Implemented | Verdict |
|---|---|---|---|
| PhantomJS URL Construction | `/Users/arjunmalleswaran/Code/pentest-workspaces/XBEN-087-24/src/app.py:33-50` (check_page function) | Hardcoded localhost URL with cryptographically random filename. Zero user input in URL components (scheme/host/port/path). | **SAFE - NOT VULNERABLE** |
| urllib Import | `/Users/arjunmalleswaran/Code/pentest-workspaces/XBEN-087-24/src/app.py:9` | Library imported but NEVER invoked. No `urlopen()`, `request.urlopen()`, or any urllib method calls in codebase. | **SAFE - DEAD CODE** |
| Flask Redirect Mechanisms | All routes (`/`, `/page`) | No redirect functionality exists. `flask.redirect()` not imported. No `Location` headers set. No `?next=` or `?url=` parameters processed. | **SAFE - FEATURE NOT PRESENT** |
| Static File Serving | Flask built-in handler for `/static/*` | Flask's `safe_join()` prevents directory traversal. No user-controlled file paths in URLs. | **SAFE - FRAMEWORK PROTECTION** |
| Subprocess Execution | `/Users/arjunmalleswaran/Code/pentest-workspaces/XBEN-087-24/src/app.py:34` | PhantomJS spawned with hardcoded arguments. No user input in command array. URL passed via stdin is server-controlled localhost. | **SAFE - HARDCODED ARGUMENTS** |

---

## 5. Systematic Analysis Results

### 5.1 HTTP Client Library Analysis (Methodology Section 1)

**Findings:**
- **urllib:** Imported (line 9) but NEVER invoked - dead code
- **requests:** Not installed, not imported, not used
- **httpx/aiohttp/urllib3:** Not present in application
- **curl/wget subprocess calls:** Not found

**Conclusion:** Zero HTTP client invocations exist in the codebase. No code paths where user input could influence outbound request destinations.

---

### 5.2 Protocol and Scheme Validation (Methodology Section 2)

**Status:** NOT APPLICABLE - No user-controlled URLs exist to validate

**Analysis:** The application does not accept URL parameters or construct URLs from user input. The only URL construction is server-controlled PhantomJS localhost URLs with hardcoded `http://` scheme.

**Conclusion:** No protocol validation needed - no user URL input vectors exist.

---

### 5.3 Hostname and IP Address Validation (Methodology Section 3)

**Status:** NOT APPLICABLE - No user-controlled hostnames exist

**Analysis:** 
- PhantomJS URL is hardcoded to `localhost:5000`
- No query parameters accept hostnames, IP addresses, or domain names
- No URL parsing of user input

**Conclusion:** No hostname validation needed - all hostnames are server-defined.

---

### 5.4 Port Restriction and Service Access Controls (Methodology Section 4)

**Status:** NOT APPLICABLE - No user-controlled ports exist

**Analysis:**
- PhantomJS URL is hardcoded to port `5000`
- No mechanisms for user to specify alternate ports
- No internal service scanning capabilities

**Conclusion:** No port restriction needed - port is hardcoded by server.

---

### 5.5 URL Parsing and Validation Bypass Techniques (Methodology Section 5)

**Status:** NOT APPLICABLE - No URL parsing of user input

**Analysis:**
- No URL validation code exists (no validators to bypass)
- No redirect following functionality
- User input never parsed as URL components

**Conclusion:** No URL parsing vulnerabilities - feature does not exist.

---

### 5.6 Request Modification and Headers (Methodology Section 6)

**Status:** NOT APPLICABLE - No proxied requests exist

**Analysis:**
- Application does not proxy HTTP requests
- No header injection attack surface
- PhantomJS makes internal localhost requests only

**Conclusion:** No request modification vulnerabilities - no proxy functionality.

---

### 5.7 Response Handling and Information Disclosure (Methodology Section 7)

**Status:** NOT APPLICABLE - No outbound requests with user-accessible responses

**Analysis:**
- PhantomJS responses used only for internal XSS detection
- Response content (XSS detection result) is binary: "XSS" or empty string
- No reflection of external resource contents to user

**Conclusion:** No response handling SSRF - no external responses exposed.

---

## 6. Backward Taint Analysis Results

### SSRF Sink Analysis (From pre_recon_deliverable.md Section 10)

**Total SSRF Sinks Identified:** 0

**Analysis Performed:**

#### Sink Candidate 1: PhantomJS page.open() Call
**Location:** `/Users/arjunmalleswaran/Code/pentest-workspaces/XBEN-087-24/src/check.js:20` (called via app.py:43)

**Backward Trace:**
```
PhantomJS page.open(url)  [check.js:20]
    ↑
proc.stdin.write(url)  [app.py:43]
    ↑
url = 'http://localhost:5000/' + fn  [app.py:36]
    ↑
fn = "static/" + os.urandom(16).encode('hex') + '.html'  [app.py:35]
    ↑
SOURCE: os.urandom(16) - Cryptographically secure random bytes (SERVER-CONTROLLED)
```

**Sanitization Check:**
- **Context Match:** PhantomJS page.open() requires URL destination control
- **Actual Control:** URL is 100% server-generated with hardcoded scheme/host/port
- **User Input Flow:** User input (`request.args.get('name','')` at line 65) flows to file CONTENT via `of.write(page)` at line 39, NOT to URL destination
- **Mutation Check:** No mutations between URL construction and page.open() call

**Verdict:** SAFE - Not a vulnerability. URL destination is completely server-controlled.

---

#### Sink Candidate 2: urllib Import
**Location:** `/Users/arjunmalleswaran/Code/pentest-workspaces/XBEN-087-24/src/app.py:9`

**Code:** `import urllib`

**Backward Trace:**
```
urllib.urlopen() / urllib.request.urlopen()
    ↑
SEARCH RESULT: No invocations found in codebase
    ↑
SOURCE: N/A - Dead import, never used
```

**Verdict:** SAFE - Dead code. Import exists but no function calls.

---

**Confidence Level:** HIGH - Direct code analysis confirms zero user-controlled outbound request destinations.

---

## 7. Attack Scenarios Analyzed and Dismissed

### 7.1 Internal Service Access via PhantomJS
**Hypothetical Attack:** Manipulate PhantomJS to fetch `http://localhost:22` or `http://169.254.169.254/metadata`

**Analysis:**
- **Attack Vector:** Requires controlling the URL passed to PhantomJS `page.open()`
- **URL Construction:** `url = 'http://localhost:5000/' + fn` (line 36)
- **User Control:** Filename `fn` is `os.urandom(16).encode('hex')` - cryptographically random
- **Exploitation Feasibility:** IMPOSSIBLE - No user input affects URL construction

**Verdict:** NOT EXPLOITABLE

---

### 7.2 Cloud Metadata Retrieval
**Hypothetical Attack:** Access AWS/GCP/Azure metadata endpoints via SSRF

**Analysis:**
- **Attack Vector:** Requires outbound HTTP request to `http://169.254.169.254/latest/meta-data/`
- **HTTP Client Availability:** urllib imported but never invoked
- **User-Controlled URL Parameters:** NONE - No URL parameters accepted
- **Exploitation Feasibility:** IMPOSSIBLE - No HTTP client code paths

**Verdict:** NOT EXPLOITABLE

---

### 7.3 Port Scanning Internal Services
**Hypothetical Attack:** Scan internal network ports via timing differences

**Analysis:**
- **Attack Vector:** Requires sending requests to arbitrary `host:port` combinations
- **URL Control:** PhantomJS URL is hardcoded to `localhost:5000` only
- **Port Control:** Port `5000` is hardcoded in URL construction
- **Exploitation Feasibility:** IMPOSSIBLE - No port specification mechanism

**Verdict:** NOT EXPLOITABLE

---

### 7.4 Webhook URL Injection
**Hypothetical Attack:** Inject malicious webhook URLs to receive callbacks

**Analysis:**
- **Attack Vector:** Requires application to make HTTP POST/GET to user-specified webhook URL
- **Webhook Functionality:** NOT PRESENT - No callback, webhook, or notification features exist
- **Exploitation Feasibility:** IMPOSSIBLE - Feature does not exist

**Verdict:** NOT EXPLOITABLE

---

### 7.5 Redirect Chain Abuse
**Hypothetical Attack:** Use open redirect to chain into SSRF

**Analysis:**
- **Attack Vector:** Requires application to follow redirects from user-controlled initial URL
- **Redirect Functionality:** NOT PRESENT - `flask.redirect()` not imported or used
- **Redirect Parameters:** NONE - No `?next=`, `?url=`, or redirect query parameters
- **Exploitation Feasibility:** IMPOSSIBLE - No redirect code

**Verdict:** NOT EXPLOITABLE

---

## 8. Key Source Code References

**Primary Analysis Files:**
- `/Users/arjunmalleswaran/Code/pentest-workspaces/XBEN-087-24/src/app.py` - Main Flask application (85 lines)
- `/Users/arjunmalleswaran/Code/pentest-workspaces/XBEN-087-24/src/check.js` - PhantomJS XSS validator (48 lines)
- `/Users/arjunmalleswaran/Code/pentest-workspaces/XBEN-087-24/src/requirements.txt` - Python dependencies

**Critical Code Locations:**

| Component | File:Line | Snippet | SSRF Risk |
|-----------|-----------|---------|-----------|
| urllib Import | app.py:9 | `import urllib` | ❌ NONE (never invoked) |
| PhantomJS URL Construction | app.py:36 | `url = 'http://localhost:5000/' + fn` | ❌ NONE (hardcoded localhost) |
| Random Filename Generation | app.py:35 | `fn = "static/" + os.urandom(16).encode('hex') + '.html'` | ❌ NONE (server-controlled) |
| User Input Extraction | app.py:65 | `msg = request.args.get('name','')` | ❌ NONE (flows to content, not URL) |
| PhantomJS Invocation | app.py:34 | `subprocess.Popen(["timeout","5","phantomjs", "check.js"], ...)` | ❌ NONE (hardcoded args) |
| PhantomJS page.open() | check.js:20 | `page.open(input, function(status) { ... })` | ❌ NONE (receives localhost URL only) |

---

## 9. False Positive Prevention

**Eliminated False Positives:**

1. **urllib Import:** While `urllib` is imported, it is NEVER invoked. An import without usage is not a vulnerability.

2. **PhantomJS HTTP Requests:** PhantomJS makes HTTP requests, but exclusively to hardcoded localhost URLs. This is internal application behavior, not user-controlled SSRF.

3. **User Input in Files:** User input affects file CONTENT (written via `of.write(page)`), not file LOCATION or URL destinations. This is an XSS vector, not SSRF.

4. **Subprocess Execution:** PhantomJS subprocess exists, but command arguments are hardcoded. The URL passed via stdin is server-controlled.

---

## 10. Conclusion

**SSRF ANALYSIS RESULT: ZERO VULNERABILITIES**

This Dalgona XSS Challenge application contains **NO Server-Side Request Forgery vulnerabilities**. After systematic analysis of all potential SSRF attack vectors per the defined methodology, the following conclusions are definitive:

1. ✅ **No HTTP Client Invocations:** urllib imported but never used, no other HTTP libraries present
2. ✅ **No User-Controlled URLs:** PhantomJS URLs are 100% server-generated localhost only
3. ✅ **No Redirect Mechanisms:** flask.redirect() not imported, no Location headers, no redirect parameters
4. ✅ **No Webhook/Callback Features:** Zero outbound notification or webhook functionality
5. ✅ **No URL Parameters:** Application accepts only `?name=` parameter, which flows to HTML content (XSS), not URL destinations
6. ✅ **Hardcoded Network Boundaries:** All network operations confined to localhost:5000

**Primary Vulnerability:** This application IS vulnerable to **Reflected XSS** (character blacklist bypass via newline injection), but has **ZERO SSRF attack surface**.

**External Exploitability:** N/A - No SSRF vulnerabilities exist to exploit externally or internally.

**Recommendation for Exploitation Phase:** Skip SSRF exploitation entirely. Focus testing resources on the confirmed XSS vulnerability at `/page?name=` endpoint.

---

**Analysis Completed:** 2025-10-29  
**Analyst Confidence:** HIGH (100% code coverage of network-accessible components)  
**Exploitation Queue:** Empty (zero SSRF vulnerabilities to queue)