If you are LinedIn user, which most probably you are, then go to your LinkedIn account right away to immediately change your password. Even better, if you have this habit of using similar password over number of websites then try changing your password across all the websites.
This is because passwords of over 6.5 million LinkedIn users were dumped (or made available in zipped format) on to a Russian hacking forum.
It is yet to ascertain if hacker was able to retrieve corresponding email addresses these passwords as well or he was able to get hold of the passwords only.
LinkedIn has confirmed the security breach. It said in a blog post:
We can confirm that some of the passwords that were compromised correspond to LinkedIn accounts.
If you want to make sure that your password was leaked out or not, head to this URL: http://www.leakedin.org/ and type your password. This website will compare your password with leaked out passwords to tell you the situation.
LinkedIn, a social networking website for professionals, has over 150 million registered users, suggesting that this security breach could have impacted at least 10 percent of total LinkedIn user base.