Nasdaq-OMX CEO on Cyber Attacks

As we sit here, there are people trying to slam into our system every day. So we have to be ever-vigilant against an ever-changing foe.
We recognize that we're under constant attack and by that I mean literally constant attack.
-- Robert Greifeld, CEO of Nasdaq OMX Group

Src: Nasdaq spends to fend off `constant' hack attacks -