A hacker is selling 167 million LinkedIn user records

The data includes hashed passwords for 117 million accounts and likely dates back to 2012

A hacker is trying to sell a database dump containing account records for 167 million LinkedIn users.

The announcement was posted on a dark market website called TheRealDeal by a user who wants 5 bitcoins, or around $2,200, for the data set that supposedly contains user IDs, email addresses and SHA1 password hashes for 167,370,940 users.

According to the sale ad, the dump does not cover LinkedIn's complete database. Indeed, LinkedIn claims on its website to have over 433 million registered members.

Troy Hunt, the creator of Have I been pwned?, a website that lets users check if they were affected by known data breaches, thinks that it's highly likely for the leak to be legitimate. He had access to around 1 million records from the data set.

"I've seen a subset of the data and verified that it's legit," Hunt said via email.

linkedin leak sale data breach Lucian Constantin

A hacker is selling 167 million stolen LinkedIn account records on a dark market website.

LinkedIn suffered a data breach back in 2012, which resulted in 6.5 million user records and password hashes being posted online. It's highly possible that the 2012 breach was actually larger than previously thought and that the rest of the stolen data is surfacing now.

LinkedIn did not immediately respond to a request for comment.

Attempts to contact the seller failed, but the administrators of LeakedSource, a data leak indexing website, claim to also have a copy of the data set and they believe that the records do originate from the 2012 LinkedIn breach.

"Passwords were stored in SHA1 with no salting," the LeakedSource administrators said in a blog post. "This is not what internet standards propose. Only 117m accounts have passwords and we suspect the remaining users registered using FaceBook or some similarity."

Best security practices call for passwords to be stored in hashed form inside databases. Hashing is a one-way operation that generates unique, verifiable cryptographic representations of a string that are called hashes.

Hashing is useful for validating passwords, because running a password through the same hashing process should always result in the same hash, allowing its comparison with one previously stored in a database.

Converting a hash back into the original password should be impossible, which is why it's safer to store hashes instead of plain text passwords. However, there are old hashing functions, such as MD5 and SHA1, that are vulnerable to various cracking techniques and should no longer be used.

When the 6.5 million LinkedIn password hashes were leaked in 2012, hackers managed to crack over 60 percent of them. The same thing is likely true for the new 117 million hashes, so they cannot be considered safe.

Worse still, it's very likely that many LinkedIn users that were affected by this leak haven't changed their passwords since 2012. Hunt was able to verify that for at least one HIBP subscriber whose email address and password hash was in the new data set that is now up for sale.

Many people affected by this breach are also likely to have reused their passwords in multiple places on the Web, Hunt said via email.

LinkedIn users who haven't changed their passwords in a long time, are advised to do so as soon as possible. Turning on LinkedIn's two-step verification is also recommended. If the LinkedIn password has been used on other websites, it should be changed there as well.

Join the CSO newsletter!

Error: Please check your email address.

Tags securityhacking

More about

Show Comments

Featured Whitepapers

Editor's Recommendations

Solution Centres

Stories by Lucian Constantin

Latest Videos

  • 150x50

    CSO Webinar: The Human Factor - Your people are your biggest security weakness

    ​Speakers: David Lacey, Researcher and former CISO Royal Mail David Turner - Global Risk Management Expert Mark Guntrip - Group Manager, Email Protection, Proofpoint

    Play Video

  • 150x50

    CSO Webinar: Current ransomware defences are failing – but machine learning can drive a more proactive solution

    Speakers • Ty Miller, Director, Threat Intelligence • Mark Gregory, Leader, Network Engineering Research Group, RMIT • Jeff Lanza, Retired FBI Agent (USA) • Andy Solterbeck, VP Asia Pacific, Cylance • David Braue, CSO MC/Moderator What to expect: ​Hear from industry experts on the local and global ransomware threat landscape. Explore a new approach to dealing with ransomware using machine-learning techniques and by thinking about the problem in a fundamentally different way. Apply techniques for gathering insight into ransomware behaviour and find out what elements must go into a truly effective ransomware defence. Get a first-hand look at how ransomware actually works in practice, and how machine-learning techniques can pick up on its activities long before your employees do.

    Play Video

  • 150x50

    CSO Webinar: Get real about metadata to avoid a false sense of security

    Speakers: • Anthony Caruana – CSO MC and moderator • Ian Farquhar, Worldwide Virtual Security Team Lead, Gigamon • John Lindsay, Former CTO, iiNet • Skeeve Stevens, Futurist, Future Sumo • David Vaile - Vice chair of APF, Co-Convenor of the Cyberspace Law And Policy Community, UNSW Law Faculty This webinar covers: - A 101 on metadata - what it is and how to use it - Insight into a typical attack, what happens and what we would find when looking into the metadata - How to collect metadata, use this to detect attacks and get greater insight into how you can use this to protect your organisation - Learn how much raw data and metadata to retain and how long for - Get a reality check on how you're using your metadata and if this is enough to secure your organisation

    Play Video

  • 150x50

    CSO Webinar: How banking trojans work and how you can stop them

    CSO Webinar: How banking trojans work and how you can stop them Featuring: • John Baird, Director of Global Technology Production, Deutsche Bank • Samantha Macleod, GM Cyber Security, ME Bank • Sherrod DeGrippo, Director of Emerging Threats, Proofpoint (USA)

    Play Video

  • 150x50

    IDG Live Webinar:The right collaboration strategy will help your business take flight

    Speakers - Mike Harris, Engineering Services Manager, Jetstar - Christopher Johnson, IT Director APAC, 20th Century Fox - Brent Maxwell, Director of Information Systems, THE ICONIC - IDG MC/Moderator Anthony Caruana

    Play Video

More videos

Blog Posts