Hundreds of similar phishing emails were being sent to American political targets, including an identical email sent on March 19 to Mr. Podesta, chairman of the Clinton campaign. Given how many emails Mr. Podesta received through this personal email account, several aides also had access to it, and one of them noticed the warning email, sending it to a computer technician to make sure it was legitimate before anyone clicked on the “change password” button.
“This is a legitimate email,” Charles Delavan,
a Clinton campaign aide, replied to another of Mr. Podesta’s aides, who had noticed the alert. “John needs to change his password immediately.”
With another click, a decade of emails that Mr. Podesta maintained in his Gmail account — a total of about 60,000 — were unlocked for the Russian hackers. Mr. Delavan, in an interview, said that his bad advice was a result of a typo: He knew this was a phishing attack, as the campaign was getting dozens of them. He said he had meant to type that it was an “illegitimate” email, an error that he said has plagued him ever since.