Data stored on cloud servers services across social media sites are off limits to searches by U.S. Custom and Border Protection when searching U.S. travelers' phones. The letter obtained by NBC News came from acting commissioner Kevin McAleenan in response to questions by Sen. Ron Wyden. In the letter, McAleenan distinguishes between data stored locally on the device and cloud data stored on remote servers. The reports suggest the ability to search the content on the phone aims to protect against child pornography, drug trafficking, terrorism and other threats.