Hackers reportedly broke into the account data of users of Snapchat, a social-sharing app especially popular among teens, and then stole and posted account information for 4.6 million users, CNN reports.
At least partial phone numbers for many users were temporarily available for download, posted Tuesday to the website SnapchatDB.info, which by later Wednesday morning had been shut down.
The app allows users to send photos and videos that promptly disappear, a useful feature for teens who try to keep their social media use hidden from the watchful gaze of parents.
The anonymous hackers said they exploited a security weakness in the app to prove a point.
"Our motivation behind the release was to raise the public awareness around the issue, and also put public pressure on Snapchat to get this exploit fixed. It is understandable that tech startups have limited resources but security and privacy should not be a secondary goal. Security matters as much as user experience does," the hackers said in a statement to technology blog TechCrunch.
The Washington Post examines questions raised about whether Snapchat delayed fixing a vulnerability.
"Even now the exploit persists," SnapchatDB said in a statement, the Post reports. "It is still possible to scrape this data on a large scale. Their latest changes are still not too hard to circumvent."
Snapchat, founded by two Stanford fraternity brothers just two years ago, rejected a $3 billion buyout offer from Facebook in November.