DOS attack

SANOJ<MU10co13>

WHAT IS DOS ATTACK??

Denial of service :It is a malicious attempt by a single person or a group of people to cause the victim, site or node to deny service to it customers.

DOS: when a single host attacksDDOS: when a multiple host attacks simultaneously.

What are the effects?

Bandwidth : network congestion

CPU time : make someone do expensive and complex calculation.

Memory : tie up system state

Symptoms of DOS attack Unusually slow network performance Unavailability of a particular website Inability to access any website Dramatic increase in spam email

received(email bomb) Disconnection of a wireless or wired

internet connection

Attack classification

DOS attack can be classified into three categories : Bandwidth/throughput attacks Protocol attacks Software vulnerability attacks

Bandwidth attacks

Leads to the problem in the “network branches”around the actual computer being attacked Ping Flood attack (ICMP echo) SYN Flood attack (DOS attack) DDOS attack (distributed DOS) UDP Flood attacks

SYN Flood attacks

Protocol attacks

These kind of attacks are carried out by using spoofed IP address

Smurf attack DNS name server attack

Smurf attacks

Packets are sent to all hosts using the broadcast address of the network

Software vulnerability attack

This attacks leads to the system crashesTypes are :- Land attack Ping to death attack Fragmentation attack and teardrop

attack

Damage and costs

The impact of DOS attack :

Hidden costs Bandwidth wastage Logging cost Extra network channel Insurance and bandwidth cost

Handling of DOS

We cannot stop DOS attack but we can reduce it by using Firewalls Switches Routers DDS based defense Clean pipes

thank you