It’s a simple case of supply and demand. The Agobot arrest has sidelined a chunk of the zombie pcs… Specifically, those infected with Agobot’s offspring, Phatbot. That leaves the zombie rental biz to Sobig, MyDoom and Bagle.

“I have no doubt it’s doubled since then as hosts are cleaned and secured,” says Andrew Kirch, of the Abusive Hosts Blocking List.

The zombie shortage is expected to put a huge dent in spammers’ growth budgets. And you think you have problems?

See for yourself at SecurityFocus.