Hackers in China, S. Korea, Germany targeted Clinton's server: AP

Low-hanging fruit: Clinton's e-mails proved irresistible to hackers, who went after her private e-mail server after she left the US State Department in February 2013.

WASHINGTON: Computer hackers in China, South Korea and Germany tried to attack Democratic presidential candidate Hillary Clinton's private e-mail server after she left the US State Department in February 2013, the Associated Press reported. 

"It was not immediately clear whether the attempted intrusions into Clinton's server were serious espionage threats or the sort of nuisance attacks that hit computer servers the world over," the AP said, citing a congressional document.