Mark Zuckerberg's Twitter and Pinterest accounts were defaced by a hacker this Monday.

The Facebook CEO was allegedly re-using passwords, which was used to log in to both accounts. The hackers, who goes by the name "OurMine," disclosed that they acquired the details of Zuckerberg among the 117 million stolen passwords from LinkedIn's database, The Guardian reported.

The hacker group apparently got through Zuckerberg's Twitter account, by posting "you were in Linkedin Database" and claiming that the password used was "dadada," while his Pinterest account's name was changed to "Hacked By OurMine Team."

"OurMine" also claimed to have logged into Zuckerberg's Instagram account, as of which Instagram is owned by Facebook, but the social media giant denied the claims, stating that "no Facebook systems or accounts were accessed,"  VentureBeat reported.

The hacker group was referring to the stolen passwords from LinkedIn back in 2012, which was released online only last month.

LinkedIn has responded since then by invalidating the information acquired because of the breach, and prompting users to reset their passwords. This may explain why, if true, the Facebook owner was using a relatively simple passphrase.

Upon realizing the breach, Twitter has responded by suspending Zuckerberg's finkd account. It has now since been activated and the threatening tweet deleted, and it seems that the account was returned under Zuckerberg's control, albeit Zuckerberg's last tweet was back in 2012.

On the other hand, Pinterest has kept silent during the fiasco, although Zuckerberg's account has now been fixed, according to the Wall Street Journal.

The hack serves well as a reminder for those who have made a habit of reusing their passwords, or not updating them.

The string of breach in security within social media websites' databases still pose a threat as hackers tend to correlate multiple sources of information to lead them to a single user, which has been apparent in Zuckerburg's case.