LinkedIn, the professional networking website, advised its members on Wednesday to change their passwords as the data of some 100 million users that were stolen in 2012 have been leaked online. In 2012, it was thought that the number of users affected by the security breach was about 6.5 million, but this week, it was found that the number is much higher.

“Yesterday, we became aware of an additional set of data that had just been released that claims to be email and hashed password combinations of more than 100 million LinkedIn members from that same theft in 2012,” LinkedIn’s Cory Scott said in a blog post. “We are taking immediate steps to invalidate the passwords of the accounts impacted, and we will contact those members to reset their passwords. We have no indication that this is as a result of a new security breach.”

Yahoo News reported that according to security blogger Brian Krebs, the security protocol of LinkedIn has been strengthened following the 2012 leaks. But he warned the users that if they have not changed their passwords since 2012, their accounts may no longer be protected.

Scott also advised users in his blog post to change passwords at regular intervals and to visit the website’s safety centre to learn more about how to ensure stronger security for the accounts. He added that LinkedIn will let those members know who needs to reset their passwords.

“We take the safety and security of our members’ accounts seriously,” Scott wrote. For several years, we have hashed and salted every password in our database, and we have offered protection tools such as email challenges and dual factor authentication.”

The First Post reported that the company recently launched a LinkedIn Students app which helps students to find jobs. It has cited the increase in demand for hiring services.