[terlisimo]

I've witnessed a few sustained (hours/days long) DDOS attacks that were straight up extortion: owners contacted with "give us money or we will keep your site offline".

Most of the time I see attacks lasting 15-20 minutes. I'm assuming it's either someone doing it "for the lulz" or some cyber warfare outfit testing their big guns.

I always consider the possibility of someone using DDOS to mask a more sophisticated attack.