Answer:
malware
Explanation:
The answer is "malware".
The secret service agent carefully analysed and suspected that the intruders have have infected the internet network system by a harmful malware that impacted the entire network system in the United States at the point-of-sale systems.
The malware is a virus which hackers and cyber criminals used to steal data and information or mislead people or government.
Thus the answer is "malware".
