#!/usr/bin/env python3
# Project: BRS-KB
# Company: EasyProTech LLC (www.easypro.tech)
# Dev: Brabus
# Date: 2025-12-27 UTC
# Status: Refactored
# Telegram: https://t.me/EasyProTech

"""
WebAssembly XSS Context

XSS through WebAssembly module loading and execution.
"""

DETAILS = {
    "title": "WebAssembly XSS",
    "severity": "medium",
    "cvss_score": 6.8,
    "cvss_vector": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N",
    "reliability": "medium",
    "cwe": ["CWE-79"],
    "owasp": ["A03:2021"],
    "tags": ["wasm", "webassembly", "xss", "browser", "module"],
    "description": """
WebAssembly XSS occurs when attackers can inject malicious WASM modules
or manipulate WASM instantiation. While WASM itself is sandboxed, it can
call JavaScript functions that perform DOM manipulation, leading to XSS.
""",
    "attack_vector": """
WEBASSEMBLY XSS VECTORS:

1. MALICIOUS MODULE LOADING
   fetch(userUrl).then(r => WebAssembly.instantiate(r))

2. INSTANTIATE URL INJECTION
   WebAssembly.instantiateStreaming(fetch(userUrl))

3. WASM-TO-JS CALLBACK
   imports = { js: { callback: eval } }
   WASM calls callback with attacker data

4. MEMORY BUFFER MANIPULATION
   Read/write to shared memory
   Inject script data

5. IMPORT OBJECT POLLUTION
   WebAssembly.instantiate(module, {
     __proto__: malicious
   })

6. STREAMING COMPILATION
   WebAssembly.compileStreaming(fetch(url))
   With attacker-controlled URL

7. TABLE FUNCTION POINTER
   Table.set(index, maliciousFunc)
   Indirect call exploitation
""",
    "remediation": """
WEBASSEMBLY XSS PREVENTION:

1. VALIDATE MODULE SOURCES
   Only load from trusted origins
   Check URL before fetch

2. CSP WASM-UNSAFE-EVAL
   Content-Security-Policy: script-src 'wasm-unsafe-eval'
   Controls WASM compilation

3. SANITIZE CALLBACKS
   Don't use eval/Function in imports
   Sanitize callback outputs

4. SUBRESOURCE INTEGRITY
   <script src="module.wasm" integrity="sha384-...">

5. RESTRICT ORIGINS
   Only load WASM from same origin
   Or specific trusted CDN

6. VALIDATE IMPORTS
   Check import object structure
   No dynamic properties
""",
}
