Smurf

It’s a version of Denial of Service attack – floods the victim with spoofed broadcast pings. A large number of pings are sent to the IP broadcast address of the victim, it responds back with broadcast to all the hosts – and these hosts simultaneously reply – causing a major lock in the network.

Ping of Death

A funny ping – ICMP packet is sent to the victim – which floods its buffer, causing the system to reboot or the network getting hanged.

DoS

The Denial of Service attack does exactly as the name suggests – prevents the users from the service. Can be generally implemented with ICMP spoofing.

SYN Flood

The SYN packets are used for connection establishment – and these SYN packets are used here to take down a computer by sending a number of useless SYN packets, and the computer becomes too busy responding to the SYNs.

Virus

Tiny programs creating a variety of bad things to computers – and they can replicate itself!

  • File virus – contained in executables like .exe, .dll, and .com.
  • Macro virus – A script to automatically carrying out a task – without the user initiating it.
  • Boot sector virus – They damage the booting process of a computer by over-writing the boot sector, creating problems like hard disk error or missing OS.

Worms

They are a lot like virus, and also they can actively replicate – without the user opening or executing them. They can propagate and destroy themselves.