"Subsequent to Yahoo's acquisition by Verizon, and during integration, the company recently obtained new intelligence and now believes, following an investigation with the assistance of outside forensic experts, that all Yahoo user accounts were affected by the August 2013 theft," the release stated on Tuesday.
The release included a link to a Yahoo web page explaining that the stolen information included names, email addresses and telephone numbers but did not include passwords, credit card data and bank account information.
"Verizon is committed to the highest standards of accountability and transparency, and we proactively work to ensure the safety and security of our users and networks in an evolving landscape of online threats," Verizon Chief Information Security Officer Chandra McMahon said in the release.
The release explained that Yahoo is sending email notifications to the additional 2 billion affected users.
Earlier this year, it has been reported that 14 million of Verizon customers had their data exposed after a third-party Israeli technology company stored user information on an insecure Amazon S3 server.
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