The hacked Yahoo account was one of two Ms Palin owned
Details of how an e-mail account of US Republican vice-presidential candidate Sarah Palin was hacked have emerged.
Following the hack, screenshots of Mrs Palin's messages, inbox, pictures and address book were posted to the Wikileaks whistle-blowing site.
It is thought the attackers exploited the password resetting system of Yahoo's e-mail service.
Details about Mrs Palin's life pulled from public sources reportedly helped defeat security questions.
Information from Wikipedia and other online databases helped to establish Mrs Palin's date of birth, zip code and other personal information.
Armed with this, the attackers convinced the Yahoo password re-setting system they warranted access and allowed them to re-set the password and then get at the account.
In an official statement Yahoo said: "Yahoo treats issues of security and privacy very seriously."
It added: "To protect the privacy of our users, we are not able to comment on the details of a specific user account."
"Generally, if Yahoo! receives reports that an account has been compromised, we investigate for suspicious activity and take appropriate action," the company said.
Mrs Palin is being investigated for her conduct as governor of Alaska
The attackers broke into Mrs Palin's email@example.com e-mail account. This account and another, firstname.lastname@example.org, owned by Mrs Palin have now been deleted.
The FBI and the US Secret Service have now begun a formal investigation into the attack and who may have been behind it.
The hackers used the CTunnel proxy service which routes web browsing through an intermediary to obscure where the attackers were based.
However, the screenshots for the attack reveal the original web address used by the proxy which may help investigators track down the miscreants.
It has been reported that records from the CTunnel proxy service are being sought by the FBI.
The attack on the e-mail account comes as questions are being asked about whether Mrs Palin used her personal e-mail accounts to carry out state business.
US law states that all e-mails relating to the official business of government must be archived and not destroyed. However, it does allow for personal e-mails to be deleted.
Mrs Palin is being investigated in Alaska for alleged abuse of power while governor of the state.