Denial Of Service Attack [Episode 2]

On a previous article you have read the basic idea and basic denial of service attack and their defense, as i described on previous article that we will share a code for SYN flooding attack.
Here is an example of exploit code written by Zakath that creates a SYN flood, the code is presented here for educational purpose only, this code is available on many web sites.

 Ping of death

• Ping of death is an another type of DOS attack that can shut down systems, and causing a great harm to the system.
• Default ICMP echo packet size of 64 bytes, many computer system could not handle the incoming packet larger the default packet size.
• In ping of death attack an attacker generates ICMP echo packets of over 65,535 bytes that is illegal.
• If you ping to a host like ping 192.168.1.1   
• What would happen if you do this thing like ping 192.168.0.1 -l 65500 -n 10000
• This, in effect, pings the target machine 192.168.0.1 continuously [10,000 times] with 64 kBs of data.

Distributed DOS

• Distributed denial of service attack or DDOS attack is a attack in which an attacker uses several machine to launch DOS attack that's why it is difficult to handle.
• In DDOS attack multiple compromised system that already infected are uses against the victim computer.
• In this case it is difficult to track the attacker because this attack generates from several IP addresses, and it is difficult to block.

Overall Defense:

There are no any single way to prevent DOS attack because of it varying nature, there are some effective way to avoid and reduce to effect of this attack.

• Install and maintain anti-virus software.
• Install a firewall, and configure it to restrict traffic coming into and leaving your computer (Firewall ,Firewall 2)
• Here is a nice article on Defense against SYN attack.

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