what is ip fragment attacks|IP fragmentation hacks

IP Fragment

IP fragments is useful in keeping tracks of the different parts of a datagram in TCP/IP suite.When the data packets arrived at the destination field then it is used to reassemble the datagrams.The identification value of all the IP fragments are same so the fragmentation offset is used to indicates the actual position of the current fragment in actual datagram packet.

Hacking/attacking IP fragments

In general the ip fragments do not coincides but a hacker can create ip fragments packets artificially,in order to forge the firewalls or routers.Suppose the second fragment of the datagram packet is inserted to the sequence by the hacker and the offset value of the second packet is less than the length of the first fragment.Then this situation may results in the overriding some bytes of the first segment on the time of reassembly at end computer.So this defected ip fragments may be responsible for the improper functioning (or crash) of the operating system.This is known as ip fragment attacks.A simple example of the ip fragmentation attack is the ping of death attack which sends the ip fragments that create the larger packets then the maximum allowed length at end computer.