This indicates that an unauthorized client attempted to write information to a PLC or other field device.
The Distributed Network Protocol (DNP3) is an industry standard for inter-operations between devices and is commonly found in SCADA systems. DNP3 enables data and command exchange between a sever and a client device. Attackers can use a write request to overwrite sensitive system information or insert incorrect data.
DNP3 servers and clients
Limit network access to vulnerable devices. Investigate the source of the traffic to prevent further attacks.