So why didn't they...
leave the control channels in place and get the AV vendors to monitor it. The AV vendors could then subscribe to the same feeds and get realtime updates on the malware being pushed out, giving them a leg up on detecting new malware. On top of this they could try and track down the controllers of the botnet and maybe even send details of the zombie PCs to the relevant ISPs.
Cutting of a single control channel is slightly inconvenient for the bad guys, but I bet they have fallback channels to enable them to regain control of their botnets. A bit like a hydra, the channels are quickly replaced and we never really get anywhere against the bad guys.
But then it's not in the interest of AV vendors to solve the problem now is it. They stand to gain a hell of a lot more by just bandaiding the situation.
While I personally profit from helping people get rid of viruses and other malware from their home computers, it is tedious and boring work and I would much rather spend my time on something more interesting.


