It’s not a single attack, but a series of intermittent attacks, director of marketing David Schwartz told ComputerWire. When we recognized we were under attack we were able to minimize disruption very quickly.

He said that the company is working with various software and hardware vendors to mitigate the attacks’ effects, and is working with the FBI on tracking down the culprits. Authorize.Net processes payments for 100,000 merchants.

Schwartz would not be drawn on the motives for the attack. In the past, DDoS attacks have been executed against others for reasons as diverse as childish bragging rights and, in a number of recent reported cases, extortion rackets.