More than 100 million user records have been stolen in a hack of the question-and-answer site Quora Inc.

The hack, described by Quora Monday as “unauthorized access to one of our systems by a malicious third party,” occurred Nov. 30. It involved the theft of data that included names, email addresses, IP logs, user IDs, encrypted passwords, user account settings, personalization data, private and public posts, linked accounts and more.

“The overwhelming majority of the content accessed was already public on Quora, but the compromise of account and other private information is serious,” Quora Chief Executive Officer Adam D’Angelo noted.

The form of the breach was not disclosed, with D’Angelo only saying that the company has “taken steps to address the issue, although our investigation is ongoing and we’ll continue to make security  improvements.” In a separate statement, Quora noted that it’s “in the process of notifying users whose data has been compromised.” SiliconANGLE can confirm that as of 10:30 p.m. EST, not all users have been notified.

Since it was founded in 2009, Quora has become particularly popular among tech-inclined people in Silicon Valley, San Francisco and beyond. The company was last in the news in April 2017 when it raised $85 million in late-stage funding with speculation that at some point it may look to go public.

Although the passwords stolen were encrypted, the hack is another reminder for users of any site to practice safe internet, including not using the same password on multiple sites.

“Users need to be concerned that there will be attempts to use their information to try to gain access at other sites that they have accounts,” Bleeping Computer noted. “It is necessary for all users to change any passwords at other sites that use the same password as Quora.”

Image: csrpazzi/Flickr