: researchers in australia have developed an underwater robot that could help save at-risk reefs. it's designed to move along damaged sections of reefs and provide microscopic basebae iic. it was recently tested at a part of the great barrier reef and dispersed 100,000 baby specimens. you get it all on "varney & company." there you go. >>> now to this. two major cyberattacks of late, one involving marriott which china was said to be behind, and the other involving tribune newspapers carried out by an unnamed foreign entity. our next guest says cyberattack are the biggest threat to u.s. national security. come on in. oz sultan. thanks for being here. make your case. >> think about it this way. we have the marriott hack, that went on for a couple of years, right, so 500 million people exposed inside of that. the problem with that is passport information, photographic information, everything you would need to clone someone's identity. then secondarily, we have this tribune breach. the tribune breach is a bigger issue. about two weeks ago, there was a breach of a power system that re