Some experts say Stuxnet could well have been far more effective and difficult to detect had the attackers not made elementary mistakes. Security consultant Tom Parker presented a compelling case at the Black Hat DC conference Tuesday. Parker analyzed the code in St.uxnet and looked at both the quality of the code itself as well as how well it did what it was designed to do. He also said that there was very little chance that one person could have put the entire attack together alone. The command-and-control mechanism is poorly done and sends its traffic in the clear.
Source: https://threatpost.com/stuxnet-authors-made-several-basic-errors-011811/74856/