http://technet.microsoft.com/en-us/security/advisory/2847140
There's a type of attack referred to as a Watering Hole Attack -- apparently at the end of April it was discovered that some US gov sites had malicious links that targeted certain groups of people, e.g. those working in an environ with nuclear materials. The type of attack was not unusual -- what was more important is that it used a zero day exploit, i.e. one that no one had seen before so there were no safeguards against it.