So far, 2012 has been the year for skeletons falling out of the IT security closet. The headlines have been hopping with stories of companies whose networks and databases were thoroughly owned by hackers for months and years at a time, often undetected until government agents came to let them know they'd been compromised and had been for a while.

Many organizations go to great lengths to keep news of these kinds of breaches under wraps if no regulated personally identifiable information is stolen, but this year many haven't kept the light of day from shining on their deep, dark security inadequacies. Dark Reading took a look at some of the most impactful long-term compromises brought to light in the past year and what these events mean to security pros.