Why haven't leading banks, including Bank of America, JPMorgan Chase, and Wells Fargo, been able to block the DDoS attacks launched against them, despite having prior warning? According to security experts, it's because the attackers appear to have compromised high-bandwidth servers--potentially at service providers--thus tapping enormous amounts of bandwidth, which they're using to launch their attacks.
The attacks illustrate the changing nature of DDoS attacks, which today are more prevalent and formidable than ever before. According to an October 2012 report from Prolexic, a DDoS protection and mitigation service provider, in the third quarter of 2012--compared to the same time period in 2011--the total number of DDoS attacks had increased 88% and the average attack bandwidth increased 230%, with attacks of 20 Gbps becoming the norm. Interestingly, however, the average attack duration decreased--between the third quarters of 2011 and 2012--from 33 hours to 19 hours.