In this research, we analyze 9 ICS protocols (5 public and 4 private) which are widely used in the critical infrastructure sectors of power, water, transportation, petroleum, and manufacturing. In each of these public and private ICS protocols, we found some common flaws which allow attackers to easily sniff unencrypted traffic and perform ICS protocol-centered attacks. These attacks include T833 - Modify Control Logic, T836 - Modify Parameter, T843 - Program Download, T856 - Spoof Reporting Message - Modbus/TCP and T855 - Unauthorized Command Message which map to MITRE ATT&CK for ICS. Attacker can be accomplished without the intruder needing to acquire authentication or authorization. Also, we provide 5 attack demos which across 1 public and 3 private protocols, to show how these common flaws will cause huge impacts such as T832 - Manipulation of View and T831 - Manipulation of Control to ICS. Finally, we demonstrate how to againist ICS network protocols attack.