Denial or refusal of service is a technique of choice for hackers hacking. This is relatively easy to make and has been a testing ground for budding pirates. In fact, hackers use this technique to gain wide recognition because of the fame and respect that the success of a DOS attack brings the intruder in the basement.
DOS attack is performed by sending packets through the data can be processed by the server of the destination network. There are many opportunities for exploits and vulnerabilities are the result of TCP / IP, IPv4 vulnerabilities in the implementation and use of system resources and target services can not answer.
There are many vulnerabilities in TCP / IP, as well as some of them listed here as they are called Ping of Death, Teardrop, SYN attacks and ground attacks.
Ping of Death
This was one of the first means of denial of service during the period in which the systems less complex than it is today. And 'now fully updated systems, which are invulnerable to attacks, Ping of Death. Ping of Death, causing the system freeze or reboot, and therefore unusable for legitimate users.
In this attack, the target system is the table with a package that exceeds the maximum allowed bytes of the TCP / IP. When the table is the target computer, the system does not use it to hang, reboot or crash.
Teardrop is an attack that exploits a vulnerability in the compilation of data packets.
When data is sent over the Internet, is first divided into smaller fragments in the source system and then configure the target system. With a gout attack, the attacker is going to confuse the goal that keeps them from setting the correct sequence of data packets.
When these packets are separated, they have an offset field in their TCP header part that will determine that each day this package fragment door.
By disrupting the number of data packets by their overlapping Offset field values, the target system becomes unable to reconstitute and forced to crash, hang or reboot.
SYN attack is a disorder of the three-way TCP / IP connection using an invalid IP address in order to SYN ACK will never be the server and wait and wait. Once the connection has been negotiated on your computer to the Internet, is a three-way connection is set.
When too many of these disorders is sent, the item will no longer have the resources to engage in a legitimate connection requests.
In a SYN attack, the attacker sends SYN packets with a server SYN packet with a source IP address wrong. When the target system receives these SYN packets with IP addresses Bad, it attempts to answer each with a SYN ACK. Now the target system expects an ACK message to come from the wrong IP address.
It is best known, as can be easily solved. An attack against the earth is like SYN attacks, but this time the attacker uses its own target IP address to create an infinite loop, where the objective is waiting for itself to send a acknowledgment that never comes because it is the target system itself is waiting to communicate with itself.
Smurf attack is a DOS attack is doing a huge number of requests for Ping to spoof IP addresses within the destination network to create traffic to the destination system, there is too much to handle. The result is that the resolution is not able to respond to legitimate users.
Distributed DoS Attacks
This is a new and improved DOS attack is a much greater threat than the same threat as the virus attacks the TWO most feared on the Internet.
Distributed DOS attack that will make it possible for attackers to flee, as it will be difficult to find because they are a group that works in tandem with each other. This kind of attack is somehow a bit difficult to find because each had less vulnerability on the target network and make their way together.