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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