The recent technical problems on July 8th causing major problems at the New York Stock Exchange, the Wall Street Journal, and United Airlines, have been described as "technical glitches" that had nothing to do with security breaches or any sort of cyber attack, but many speculate that we have not heard the whole story.
John McAfee makes a good point noting that it takes more than a couple hours after a major failure to rule out the possibility of malicious activity. So how were these companies so sure that in each case the problem was a simple technical glitch? Even if a problem is the result of a hardware failure, how could malicious activity be ruled out so quickly? Remember Stuxnet?
This is a good "non-mainstream media" article on the subject: