It seems that hackers could have breached servers of Yahoo! and leaked 453,000 user credentials stored in plain text. According to the cybercrooks they used a union-based SQL injection method and penetrated Yahoo! subdomain.
"We hope that the parties responsible for managing the security of this subdomain will take this as a wake-up call, and not as a threat," the said the hackers. - There have been many security holes exploited in webservers belonging to Yahoo! Inc. that have caused far greater damage than our disclosure. Please do not take them lightly. The subdomain and vulnerable parameters have not been posted to avoid further damage."
Hacktivists apparently neglected to remove the host name from the data which is dbb1.ac.bf1.yahoo.com. It is associated with the Yahoo! Voices platform, formerly known as Associated Content.
At this moment the website that hosted the leaked data is down. We cannot tell whether it was shut down by it’s ISP, DDoSed or just is not capable of handling visitors’ flow.