Shields Up!: Global cyberattack investigation leads to…Miami?

When a large scale cyberattack began hitting the United States and South Korea over the July 4th weekend, the accusations and speculation regarding who was to blame began flying. South Korea insisted North Korea must be to blame. The U.S. wondered if it was the work of Russia or maybe China. Researchers claimed to have found the master control server in the U.K. So who is really to blame for the attack, which is still not over?