#!/usr/bin/env python3
"""
Safe Vulnerability Checker for CVE-2026-12485 (GeoVision GV-I/O Box 4E DVRSearch)

This script sends a benign UDP probe to port 10001 to:
1. Detect if the DVRSearch service is running.
2. Check basic response behavior.
3. Perform a **safe** length test (does NOT trigger the overflow).

WARNING:
- This is for authorized testing only on systems you own/control.
- Do not use on production systems without permission.
- The real vulnerability can lead to RCE/crash with longer payloads.
"""

import socket
import sys
import argparse
import time

def send_probe(target_ip, port=10001, timeout=3):
    """Send a safe probe and observe response."""
    try:
        sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
        sock.settimeout(timeout)
        
        # Safe probe: CMD_IP_SET like structure with short/normal data
        # Based on public vulnerability details (small payload)
        probe = bytearray([0x00, 0x00, 0x00, 0x01])  # Example command header (CMD_IP_SET guess)
        probe += b"192.168.1.100"  # Short IP
        probe += b"\x00" * 20      # Padding
        
        print(f"[+] Sending safe probe to {target_ip}:{port} ...")
        sock.sendto(probe, (target_ip, port))
        
        try:
            data, addr = sock.recvfrom(2048)
            print(f"[+] Received response ({len(data)} bytes) from {addr}")
            print(f"[+] Service appears active. Response preview: {data[:64]}...")
            return True, data
        except socket.timeout:
            print("[-] No response received (timeout). Service may not be listening or filtered.")
            return False, None
            
    except Exception as e:
        print(f"[-] Error: {e}")
        return False, None
    finally:
        sock.close()

def safe_length_test(target_ip, port=10001, timeout=3):
    """Send incrementally larger but still safe payloads (well below overflow threshold)."""
    print("\n[+] Performing safe length test (non-crashing)...")
    sizes = [50, 100, 200, 400]  # Conservative sizes
    
    for size in sizes:
        try:
            sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
            sock.settimeout(timeout)
            
            payload = b"A" * size
            header = bytearray([0x00, 0x00, 0x00, 0x01])
            probe = header + payload
            
            print(f"    Testing payload size: {len(probe)} bytes...")
            sock.sendto(probe, (target_ip, port))
            
            try:
                data, _ = sock.recvfrom(2048)
                print(f"    [+] Size {len(probe)} -> Response received ({len(data)} bytes)")
            except socket.timeout:
                print(f"    [-] Size {len(probe)} -> No response")
            
            time.sleep(0.5)
        except Exception as e:
            print(f"    [!] Error on size {size}: {e}")
        finally:
            sock.close()

def main():
    parser = argparse.ArgumentParser(description="Safe CVE-2026-12485 Checker")
    parser.add_argument("target", help="Target IP address")
    parser.add_argument("-p", "--port", type=int, default=10001, help="UDP port (default: 10001)")
    parser.add_argument("--length-test", action="store_true", help="Run safe length test")
    args = parser.parse_args()

    print("=" * 60)
    print("Safe CVE-2026-12485 (GV-I/O Box 4E DVRSearch) Checker")
    print("=" * 60)
    print(f"Target: {args.target}:{args.port}")
    print("This script does NOT exploit the vulnerability.\n")

    active, _ = send_probe(args.target, args.port)
    
    if active and args.length_test:
        safe_length_test(args.target, args.port)
    
    print("\n" + "=" * 60)
    print("Recommendation:")
    print("- If service responds → Update firmware immediately (GV-IOBOX_2026-06-01).")
    print("- Block UDP/10001 from untrusted sources.")
    print("- Full advisory: https://talosintelligence.com/vulnerability_reports/TALOS-2026-2377")
    print("=" * 60)

if __name__ == "__main__":
    if len(sys.argv) < 2:
        print("Usage: python3 CVE-2026-12485-check.py <target_ip> [--length-test]")
        sys.exit(1)
    main()