Presidential candidates may be vulnerable to foreign hackers, US says

US national intelligence already has 'some indications' that campaign networks are being spied on, as government works to tighten security against cyberattacks

The United States sees evidence that hackers, possibly working for foreign governments, are snooping on the presidential candidates, the nation's intelligence chief said on Wednesday. Government officials are working with the campaigns to tighten security as the race for the White House intensifies.

The activity follows a pattern set in the last two presidential elections. Hacking was rampant in 2008, according to US intelligence officials, and both Barack Obama and Mitt Romney were targets of Chinese cyber-attacks four years later. Despite that history, cyber experts say neither Donald Trump's nor Hillary Clinton's campaign networks are secure enough to eliminate the risk.