Equifax on Thursday expanded for the second time its estimate of the number of consumers impacted by its 2017 massive data breach.

The Atlanta-based credit bureau announced that it has now confirmed the identities of an additional 2.4 million U.S. consumers whose names and partial driver's license information were stolen by hackers who penetrated Equifax's firewalls sometime last year.

The company also noted that its forensic experts had determined that the hackers were primarily focused on stealing Social Security numbers.

Equifax's new revelation brings the total of consumers potentially affected by the hack to 148 million.

Equifax did not discover the hack until July 2017 and did not notify the public until September of that year.

Equifax initially announced that 143 million consumers whose financial data and personal identifying information the credit bureau had stockpiled was potentially compromised. Equifax later increased that number to 145.5 million.

In a news release issued Thursday morning, Equifax said the additional compromised consumers were uncovered during a forensic examination of the company's databases. They were not included in the original population of those affected because Equifax data did not include consumers' home addresses and drivers' license information was incomplete.

“This is not about newly discovered stolen data,” Equifax interim CEO Paulino do Rego Barros Jr. said in a written statement included in the release. “It's about sifting through the previously identified stolen data, analyzing other information in our databases that was not taken by the attackers, and making connections that enabled us to identify additional individuals.”

Equifax said it intended to notify the newly identified consumers and will offer identity theft protection and credit monitoring services at no cost.

Equifax also claimed the company's' forensic experts had found “no evidence” that Equifax's core consumer, employment and income or commercial credit reporting databases were accessed by hackers.

Meanwhile, more than 300 proposed class action suits have been filed on behalf of individual consumers, financial institutions and businesses that may have been impacted by the data breach. Those suits have been consolidated in pending multidistrict litigation in U.S. District Court in Atlanta.