Employees of the Quora knowledge sharing service discovered that unknown hackers managed to access one of the company’s systems. The attack could affect about 100 million users. Quora reported about it in its blog.
Data that have been compromised may include user name, e-mail address, encrypted password and user data from a linked network, if it was used to log in to Quora.
Service representatives notified law enforcement authorities of the attack and started a thorough investigation in order to understand how the hackers could have gained access to confidential information of millions of users.
The leak was discovered on Friday, November 30th, but the company’s official statement was not made until after the weekend. The company is in the process of sending out e-mails to the users affected to notify them of the incident.
The Quora service created by Facebook co-founders Adam d’Angelo and Charlie Cheever is meant for knowledge sharing. Users can ask questions on various subject, and other users’ answers are ranked according to the ratings they get. To organize questions across its various sections, Quora uses a machine learning algorithm.
100 million users apparently represent a significant part of the service’s audience. In 2015, the company’s CEO Adam d’Angelo claimed that Quora had about 200 million unique users.
Large-scale data breaches are not uncommon today, and big corporations are also vulnerable to hacker attacks. For example, last week, data on 500 million Marriott hotel guests appeared online, and in September a hacker managed to collect personal data on 29 million Facebook accounts.