#!/usr/bin/env python3

"""
Project: BRS-KB (BRS XSS Knowledge Base)
Company: EasyProTech LLC (www.easypro.tech)
Dev: Brabus
Date: 2025-12-26 UTC
Status: Created
Telegram: https://t.me/EasyProTech

Knowledge Base: WebAssembly GC XSS
"""

DETAILS = {
    "title": "Cross-Site Scripting (XSS) via WebAssembly Garbage Collection",
    "severity": "high",
    "cvss_score": 7.5,
    "cvss_vector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:L/A:N",
    "reliability": "medium",
    "cwe": ["CWE-79", "CWE-119"],
    "owasp": ["A03:2021"],
    "tags": ["xss", "wasm", "gc", "garbage-collection", "memory", "proposal"],
    "description": """
WebAssembly GC (proposal) adds garbage collection to WASM. XSS vulnerabilities occur when
user input controls GC object creation, type definitions, or memory operations without validation.

SEVERITY: HIGH
Low-level memory access can lead to memory corruption and arbitrary code execution.
""",
    "attack_vector": """
WASM GC TYPE INJECTION:
(type $UserType (struct (field $data (ref string))))
// XSS if type definition is user-controlled

WASM GC OBJECT CREATION:
struct.new $UserType (string.const userInput)  // XSS if userInput is malicious

WASM GC MEMORY ACCESS:
local.get $index
struct.get $UserType $data  // XSS if index is out of bounds

WASM GC ARRAY INJECTION:
array.new $ArrayType (i32.const userInput)  // XSS if size is controlled

WASM GC WITH JAVASCRIPT:
const wasmModule = await WebAssembly.instantiateStreaming(
  fetch('module.wasm'),
  {
    env: {
      getData: () => userInput  // XSS if returned to JavaScript
    }
  }
);
""",
    "remediation": """
DEFENSE:

1. Validate all WASM type definitions
2. Validate GC object data before creation
3. Bounds check all memory access
4. Sanitize data passed between WASM and JavaScript
5. Use TypedArray for safe memory access

SAFE PATTERN:
function validateWasmData(data) {
  if (data.length > 1024) {
    throw new Error('Data too large');
  }
  // Additional validation
  return data;
}
struct.new $UserType (string.const validateWasmData(userInput))

MEMORY VALIDATION:
function safeMemoryAccess(wasmMemory, index) {
  if (index < 0 || index >= wasmMemory.length) {
    throw new RangeError('Index out of bounds');
  }
  return wasmMemory[index];
}

OWASP REFERENCES:
- CWE-79: Cross-site Scripting
- CWE-119: Improper Restriction of Operations within Bounds
- WebAssembly GC Proposal
""",
}
