Smurf attack

Definition

A smurf attack is a way of generating significant computer network traffic on a victim's network. This is a type of denial-of-service attack that floods a target system via spoofed broadcast ping messages.

Overview

This type of attack relies on a perpetrator sending a large amount of ping traffic to IP broadcast addresses, all of which have a spoofed source IP address of the intended victim. If the routing device delivering traffic to those broadcast addresses delivers the IP broadcast to all hosts (for example via a layer 2 broadcast), most hosts on that IP network will take the ping request and reply to it with an echo reply, multiplying the traffic by the number of hosts responding. On a multi-access broadcast network, hundreds of machines might reply to each packet.

In the late 1990s, many IP networks would participate in smurf attacks (that is, they would respond to pings to broadcast addresses). Today, thanks largely to the ease with which administrators can make a network immune to this abuse, very few networks remain vulnerable to smurf attacks.