Capital One Jan 2013 2
People walk past a Capital One banking center in New York City''s financial district. Reuters

A hacker has exposed the personal information of roughly 100 million American and 6 million Canadian customers of financial banking giant Capital One (COF).

Personal information such as names and addresses were leaked in the sprawling data breach. In addition, there could be as many as 140,000 Social Security numbers and 80,000 bank accounts exposed.

One million Canadian social insurance numbers could also be compromised as part of the breach.

The hacker, who appeared in a Seattle court Monday, posted the information on open-source coding platform Github between March 12 and July 17.

One of the users on Github notified Capital One and the company discovered that the hacker was Paige Thompson, a former software engineer in her early 30's who used to work for Amazon in Seattle.

Thompson made little effort to hide her identity online and understood that her actions were illegal.

Thompson was charged by the FBI with computer fraud and abuse. The FBI found documents that referenced Capital One and Amazon during a raid on Thompson's house.

The incident will cost Capital One between $100 to $150 million.

Those who applied for credit cards between 2005 and early 2019 may be affected. There are some guidelines for customers who believer their information may have been exposed.

The breach comes after consumer credit reporting company Equifax pays $700 million in a settlement with the Federal Trade Commission after a data breach revealed the personal information of 147 million people in September 2017. The company has been offering $125 or free credit monitoring to those affected.