Facebook Admits It Left Hundreds of Millions of User Passwords Exposed

Facebook inadvertently left hundreds of millions of usernames and passwords in clear text on its own internal servers. Apparently, the data was never leaked and the information was not abused.

Facebook Data Sharing Probe

In a shocking admission on March 21, Facebook revealed that it left "hundreds of millions" of user passwords exposed and unencrypted on several internal Facebook systems.

Facebook has not publicly disclosed how long the passwords were left unencrypted, though the company stated that it has no evidence that the passwords were ever visible to anyone outside of Facebook. Additionally, Facebook claims that the unencrypted passwords were never improperly accessed or abused.

"As part of a routine security review in January, we found that some user passwords were being stored in a readable format within our internal data storage systems," Pedro Canahuati, vice president of engineering, security and privacy, wrote in a news advisory. "This caught our attention because our login systems are designed to mask passwords using techniques that make them unreadable." 

Canahuati stated that Facebook has since fixed the issues and will be contacting impacted users to alert them of the potential risk. While Facebook has not provided a specific number of users that have been impacted, Canahuati stated that hundreds of millions of Facebook Lite users are likely impacted. Facebook Lite is a version of Facebook provided to users in areas with low bandwidth. Additionally, tens of millions of Facebook as well as Instagram users are impacted and will be contacted by the social media giant.

How Did This Happen?

Facebook has not publicly stated why the passwords were left unencrypted and available on its internal systems. The company stated that in its normal course of operations, passwords are protected with a number of mechanisms so they are not viewable.

Among the techniques used by Facebook is one known as cryptographic hashing, which essentially "hashes," or encrypts, the data such that it is unreadable as plain text. Additionally, Facebook makes use of a technique known as "salting" the hash, which provides an extra layer of protection for the cryptographic hash in an attempt to make it more resilient.

"In the course of our review, we have been looking at the ways we store certain other categories of information—like access tokens—and have fixed problems as we’ve discovered them," Canahuati wrote. "There is nothing more important to us than protecting people’s information, and we will continue making improvements as part of our ongoing security efforts at Facebook."

The revelation is the latest in a string of troubling episodes that have hit the social media giant in recent months. In September 2018, Facebook reported a data breach that involved attackers gaining access to user access tokens. In that breach, some 90 million Facebook users were impacted. Facebook has also been the subject of intense scrutiny over data misuse from a variety of incidents.

What Facebook Users Should Do

While Facebook has stated that the unencrypted passwords were not misused, it's important that users still take steps to reduce risk. There are several key steps that Facebook recommends:

  • Use two-factor authentication. With two-factor authentication (2FA), a second "factor," or password, is needed to gain access to account.
  • Update passwords. Though Facebook doesn't have any evidence of misuse, the incident is a good opportunity for users to update and change their Facebook and Instagram passwords.
  • Don't reuse passwords. A key threat comes from users having the same password on multiple sites.

Sean Michael Kerner is a senior editor at eWEEK and InternetNews.com. Follow him on Twitter @TechJournalist.

Sean Michael Kerner

Sean Michael Kerner

Sean Michael Kerner is an Internet consultant, strategist, and contributor to several leading IT business web sites.