Question: what are the major risks in network security?
Answer: Viruses and Worms. Computer viruses and worms are destructive malicious programs designed to infect core systems, destroying essential system data and making networks inoperable. ... 
Drive-by Download Attacks. ... 
Botnets. ... 
Phishing Attacks. ... 
Exploit Kits. ... 
DDoS (Distributed Denial of Service) ... 
Ransomware. ... 
Cryptojacking.