22:32World Business ReportFirst broadcast 2016/12/15 22:32 GMT: Yahoo Reveals A Billion User Accounts HackedBBC World Service Duration: 27 minutes Thu 15th Dec 2016, 22:32 on BBC World Service OnlineAvailable for over a yearListen nowYahoo has said a billion of its user accounts were hacked in a cyber attack. Show more GenresFactualMoneyFormatsBulletinsBrandWorld Business Report Source: BBC Online