[glugger]

They are most likely just hiring a botnet. Like this:
http://www.webroot.com/blog/2012/06/06/d...ainstream/

Quote:

Thanks to the increasing availability of custom coded DDoS modules within popular malware and crimeware releases, opportunistic cybercriminals are easily developing managed DDoS for hire, also known as “rent a botnet” services, next to orchestrating largely under-reported DDoS extortion campaigns against financial institutions and online gambling web sites.

In this post, I’ll profile a managed DDoS for hire service, offering to “take down your competitor’s web sites offline in a cost-effective manner”.