(Adds share price, background on data breach)
Sept 19 (Reuters) - Massachusetts Attorney General Maura Healey filed a lawsuit on Tuesday against credit reporting firm Equifax Inc following a breach that exposed the personal data of as many as 143 million people, including 3 million in the state.
Equifax's share price has fallen by about one-third since it disclosed the data breach, which included sensitive data like Social Security numbers, on Sept. 7. Equifax shares dipped 0.1 percent to $94.25 on Tuesday.
"... Equifax knew about the vulnerabilities in its system for months, but utterly failed to keep the personal information of nearly three million Massachusetts residents safe from hackers," said Healey said in a statement.
"... Equifax needs to pay for its mistakes, make our residents whole, and fix the problem so it never happens again," Healey added.
The lawsuit seeks civil penalties, disgorgement of profits, restitution, costs, and attorneys fees.
The Equifax breach has also affected about 100,000 Canadians, it said on Tuesday. "The information that may have been breached includes name, address, Social Insurance Number and, in limited cases, credit card numbers," Equifax said. (Reporting by Diane Bartz in Washington; Editing by Chizu Nomiyama and Jeffrey Benkoe)