NEW: Hack impacted users of Yahoo Voices, a Web news product Yahoo confirmed on Thursday the hack of Yahoo Voices, part of its news service, saying "approximately 400,000" usernames and passwords were stolen. But in a written statement, the company said that less than 5% of the breached Yahoo accounts had valid passwords. "At Yahoo! we take security very seriously and invest heavily in protective measures to ensure the security of our users and their data across all our products," the statement said. We are fixing the vulnerability that led to the disclosure of this data, changing the passwords of the affected Yahoo! users and notifying the companies whose users accounts may have been compromised. Yahoo apologized in the statement and urged users to change their passwords on a regular basis. Perhaps due to the similarity of the names, some early reports from security analysts and others identified the hack as impacting users of Yahoo Voice, the site's Web phone service.