An attacker may execute a ICMP Fragmentation attack against a target with the intention of consuming resources or causing a crash. The attacker crafts a large number of identical fragmented IP packets containing a portion of a fragmented ICMP message. The attacker these sends these messages to a target host which causes the host to become non-responsive. Another vector may be sending a fragmented ICMP message to a target host with incorrect sizes in the header which causes the host to hang.
This attack may be mitigated through egress filtering based on ICMP payload so a network is a "good neighbor" to other networks. Bad IP implementations become patched, so using the proper version of a browser or OS is recommended.