Yahoo reported on Thursday that some of its users' e-mail accounts may have been targeted in a security breach of a third-party database.
"Recently, we identified a coordinated effort to gain unauthorized access to Yahoo Mail accounts," the company said in a blog post on its Tumblr site. "Upon discovery, we took immediate action to protect our users, prompting them to reset passwords on impacted accounts."
The company told users who may have been affected to reset their passwords. It has also implemented a second sign-in verification to allow users to re-secure their accounts.