(CNN) - Hackers posted online what they say is login information for more than 450-thousand Yahoo users. An anonymous group dumped the stolen passwords onto another web page. According to that site, the data was released as a wake-up call.
The note warned Yahoo to take a closer look at its current security coverage.
The breach impacted users of Yahoo Voices, an online publishing tool. But it could be much more widespread.
Many people re-use passwords across the internet.
Yahoo apologized today and urged users to change their passwords regularly. They said less than five percent of the breached accounts had valid passwords.