Distributed denial-of-service (DDoS) c do not have to be bandwidth-intensive to be disruptive and hard to mitigate.

Earlier this month, Imperva mitigated an attack against one of its clients that exceeded 500 million packets per second, making it possibly the largest DDoS attack by packet volume ever recorded.

The January 10 attack was a so-called SYN flood, in which an attacker attempts to overwhelm a target computer by sending it TCP connection requests faster than the machine can process them. In this case, the attacker sent both a flood of normal SYN packets and a large SYN flood, involving packets of between 800 and 900 bytes, at the target using a highly randomized and likely spoofed set of source ports and addresses, according to Imperva.