Equifax has revealed additional information about the massive data breach that hit the firm. The credit rating firm confirmed that hackers may have stolen personal and financial data of 100,000 Canadian users. Hackers may have accessed users' names, addresses, social insurance numbers and in some cases even credit card data.

The firm said that it will notify every affected customer by mail. Equifax also said that it will provide a free credit monitoring and identity theft protection to affected Canadian users for a year.

"We apologize to Canadian consumers who have been impacted by this incident," said Lisa Nelson, President and General Manager, Equifax Canada. "We understand it has also been frustrating that Equifax Canada has been unable to provide clarity on who was impacted until the investigation is complete. Our focus now is on providing impacted consumers with the support they need."

Equifax said that its Canadian systems were not affected by the incident. However, the firm is still investigating the historic breach. "While our investigation is ongoing and this information may change, at this point, we believe that the incident involves potential access to the personal information of approximately 100,000 Canadian consumers. Should that number change during ongoing investigations, we will assuredly keep those impacted consumers informed of the details as readily as that information is made available to Equifax," the firm said in a statement.

Last week Equifax revealed that 400,000 UK consumers' data may also have been stolen by hackers. The massive breach affected over 143 million US users. Two of the firm's top executives have since departed and the firm is now facing increased scrutiny from US authorities, as well as major class action lawsuits.

As the scale of the historic data breach continues to expand, the identity of the hackers who perpetrated the breach remains unknown. It recently came to light that Equifax suffered a separate hack in March, before it was hit again by hackers in July.