IP Fragment Overlap Attack
IP Fragment Overlap Attack is a type of cyber attack that exploits vulnerabilities in the way Internet Protocol (IP) packets are reassembled by a receiving host. When a large packet is sent over the internet, it is fragmented into smaller IP packets to traverse the network. The receiver then uses the offset field in the IP header to reassemble the packets into the original message. However, if an attacker purposely sends overlapping IP fragments, it could cause the receiver to mishandle the packets and potentially crash the system.
For example, imagine you are trying to send a message in several envelopes. You put the message in the first envelope, and then cut the second envelope in half so that it overlaps with the first envelope. You continue to do this with all the subsequent envelopes until the message is sent in fragments. When the receiver tries to reassemble the message, it would have a problem because the overlapping envelopes would be misaligned and could result in important parts of the message being lost or corrupted.
To prevent such attacks, firewalls and intrusion detection systems are used to detect and prevent the transmission of such illegal fragments. Additionally, network administrators can configure their systems to block the use of overlapping fragments in accordance with the RFC standard.