Researchers discovered the 150GB volume of biggest and most comprehensive email unprotected MongoDB that leaked 800 Million Email data online that belongs to

The leaked email contains sensitive information including personally identifiable information (PII) and the complete data being available in public that can be accessed by anyone on the internet.

This Database exactly contains 808,539,939 records with the name of
“mailEmailDatabase” where there is 3 different folders under the folder named as a “collection”.

  • Emailrecords (count: 798,171,891 records)
  • emailWithPhone (count: 4,150,600 records)
  • businessLeads (count: 6,217,358 records)

Researchers dive deeper and analyse the data using with Troy Hunt’s HaveIBeenPwned database that reveals leaked data is one of the collections of previously leaked data but this databased contain completely unique data.

“Although, not all records contained the detailed profile information about the email owner, a large amount of records were very detailed. We are still talking about millions of records.”

Further analysis revealed that the data owned by a company named ‘ that the largest ‘Enterprise Email Validation service provider.

‘ provide a validation service for its customer and it validate the emails and send the result back to the customer about the valid email list.

According to the security researcher , the email validation methods works in the following way,

  1. Someone uploads a list of email addresses that they want to validate.
  2. has a list of mail servers and internal email accounts that they use to “validate” an email address.
  3. They do this by literally sending the people an email. If it does not bounce, the email is validated.
  4. If it bounces, they put it in a bounce list so they can easily validate later on.

In practically, If cybercriminals have a 100 of companies hacked email address in millions but he doesn’t know which one is valid and invalid.

In this case, he uploads all of his potential email addresses to a service like then the email verification service sends tens of thousands of emails to validate these users in order to identify valid and invalid email address.

” Each one of the users on the list gets their own spam message saying “hi”. Then the threat actor gets a cleaned, verified, and valid list of users at these companies. Now he knows who works there and who does not, and he can start a more focused phishing or brute forcing campaign.” researcher said.

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