Crucial Exams

Certified Ethical Hacker (CEH) Practice Question

During an internal assessment of a water treatment facility, you gain unauthenticated TCP access to a legacy PLC that controls the plant's chemical-dosing pumps. An Nmap scan reports port 502 open, and packet inspection confirms Modbus/TCP traffic. To overwrite the chlorine set-point stored in a single holding register, which Modbus function code should you transmit to the device?

  • Function code 0x05 - Write Single Coil

  • Function code 0x10 - Write Multiple Registers

  • Function code 0x03 - Read Holding Registers

  • Function code 0x06 - Write Single Register

Certified Ethical Hacker (CEH)
Mobile Platform, IoT, and OT Hacking
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