An API flaw that was patched in January allowed for the theft of over 5.4 million Twitter user records that contained private information. These records were made available for free sharing on a hacker forum.

A security researcher has also revealed another enormous, possibly more significant, data dump of millions of Twitter records, illustrating how widely this flaw was utilised by threat actors.
The material is made up of public data that has been scraped as well as secretive email addresses and phone numbers.

The data breach on Twitter
In July of last year, a threat actor started charging $30,000 for the personal data of more than 5.4 million Twitter users.

The majority of the material was made up of publicly available details such Twitter IDs, names, login names, localities, and verified statuses; however, there was also private information like phone numbers and email addresses.

This information was gathered in December 2021 by utilising a Twitter API flaw that was made public through the HackerOne bug bounty programme. This flaw allowed users to submit their phone numbers and email addresses to the API in order to obtain the corresponding Twitter ID.

The threat actors might then use this ID to scrape the account’s public data to generate a user record with both private and public data. The HackerOne disclosure may have been disclosed, but BleepingComputer was informed that numerous threat actors were using the flaw to steal personal data from Twitter.

Twitter confirmed it had experienced a data breach due to an API issue resolved in January 2022 after BleepingComputer sent them a sample of the user details.

This past weekend, Pompompurin, the proprietor of the Breached hacking site, revealed to BleepingComputer that they were in charge of exploiting the flaw and producing the enormous dump of Twitter user data after another threat actor going by the name of “Devil” disclosed the vulnerability to them.

Nearly 7 million Twitter profiles with private information were found overall, including the 5.4 million records for sale and an additional 1.4 million suspended user profiles that were gathered via a separate API.

Pompompurin said that this second data dump was only privately distributed to a select group of individuals and was not sold.

Sharing of Twitter data on a hacking forum
The 5.4 million Twitter records have now been freely posted on a hacking forum twice—once in September and most recently on November 24.

This data, which includes 5,485,635 records of Twitter users, was for sale in August, and Pompompurin has confirmed this to BleepingComputer.

These records include the account’s Twitter ID, name, screen name, verified status, location, URL, description, follower count, account creation date, friends count, likes count, statuses count, and profile image URLs, along with either a private email address or phone number.

An even larger data dump was produced in secret.
Although it is troubling that threat actors gave out 5.4 million records, it is also claimed that the same vulnerability was used to create a much larger data dump.

This data dump may comprise tens of millions of Twitter records, including public data like verified status, account names, Twitter IDs, bios, and screen names, as well as personal phone numbers gathered using the same API problem.

Security expert Chad Loder, who initially reported the information on Twitter and was suspended shortly after publishing it, is the source of the information on this more serious data leak. Later, Loder published a sample of this wider data breach on Mastodon with redactions.

“I recently learned about a significant Twitter data breach that affected millions of US and EU Twitter accounts. I got in touch with a small number of the impacted accounts, and they confirmed that the stolen information is true. This breach did not happen until 2021, “Shared on Twitter by Loder

A sample file from this previously unreported Twitter data dump, which contains 1,377,132 phone numbers for people in France, has been discovered by BleepingComputer.

The phone numbers in this leak have since been verified by a large number of people, proving that this additional data breach is legitimate.

Additionally, none of these phone numbers were part of the initial data sold in August, demonstrating how much more user data was available to threat actors than Twitter had previously reported and how much broader Twitter’s data breach was than had been previously disclosed.

Additionally, Pompompurin informed BleepingComputer that they were not in charge of and were unaware of the creator of the recently found data leak, proving that other parties were utilising this API vulnerability.

According to information obtained by BleepingComputer, this recently found data dump comprises of a large number of files divided up by region codes and countries, including Europe, Israel, and the USA.

Although we were informed that it contains more than 17 million records, we were unable to independently verify this.

It is crucial to carefully review any email that purports to be from Twitter because this information might potentially be used for targeted phishing attacks to get login credentials.

You should disregard and delete any emails that encourage you to log in to a non-Twitter domain and claim that your account has been suspended, there are login problems, or you are about to lose your verified status. These emails are likely phishing attempts.

On Thursday, BleepingComputer contacted Twitter on this additional data leak of personal data, but has not heard back.