When Daniel DePetris, a U.S.-based foreign affairs analyst, received an email in October from the director of the 38 North think tank commissioning an article, it seemed to be business as usual.

It wasn't. The sender was actually a suspected North Korean spy seeking information, according to those involved and three cybersecurity researchers.

Instead of infecting his computer and stealing sensitive data, as hackers typically do, the sender appeared to be trying to elicit his thoughts on North Korean security issues by pretending to be 38 North director Jenny Town.