Denial of Service (DOS) attacks

 Denial of Service (DOS) attacks are intended to shut down the servers for a period of time. To make site nonfunctional for a time the main part of attack is DOS attack. DOS attacks are usually doing by following methods:

1. Send unlimited amount of packets to the server.

2. Executing malwares

3. Teardrop attack

4. Application level flood

Sending unlimited packets by ping command is also known as ICMP flood. This method can be done in the following way.


A simple DOS attack code would be:

ping {ip} -t -l 20000

On command prompt window you can type the following command. This command sends 20000 bytes of data to the ip, in a single packet. The -t is to ping the specified host until stopped and -l is to specify the buffer size. A Teardrop attack involves sending mangled Internet Packet fragments with overlapping, over-sized, payloads to the target machine. In peer to peer attack thousands of computers will try to access a single computer at the same time. It will break down all the connection from the server at last the target machine will fail. Application level flood is by the mis-programming of an application installed on the server.So it will consume a major portion of server computing power and memory.

DOS attack with ping flood will work only if the following cafeterias are satisfied:

1. Attacker should have higher bandwidth than the victim.

2. Victim should respond to the ping requests