Symantec, one of the top anti-virus solution developers in the world, has been focusing on developing stronger defense solutions which especially deal with malware that produce a lot of zombies.
The most frequent situation in cyber attacks recently is that a few host computers technically transmit malware to tens of thousands of other computers in a short period of time, which causes individual computers being infected by drive-by downloads or click-jacking. Then, infected computers become part of a botnet, a network of zombie computers which carry out spam tasks without letting their owners realize what they are doing every day.
These host computers frequently transmit malware in many different indirect methods to avoid antivirus detection. That forced Symantec to develop many different types of solutions such as heuristic systems, notoriety detection systems and a white-listing system which all deal with the possible types of indirect methods of infection.
However, it is not possible for anyone to develop perfect defense solutions until now, especially for the attacks such as DDoS, which cause overloaded situations in banking systems. There are basically no ways to control those overloaded situations even though a company provides a lot of systems and technologies to potential victims. The best possible way to protect victims is to sort out as many hosts as possible by using developed solutions and provide anti-virus solutions to individual computers so that they do not become a part of a botnet again.