Yahoo has sent out another round of notifications to users, warning some that their accounts may have been breached as recently as last year. The accounts were affected by a flaw in Yahoo’s mail service that allowed an attacker—most likely a “state actor,” according to Yahoo—to use a forged “cookie” created by software stolen from within Yahoo’s internal systems to gain access to user accounts without a password.
Yahoo informed some users in e-mails this week that “Based on the ongoing investigation, we believe a forged cookie may have been used in 2015 or 2016 to access your account.” The messages are regarding possible breaches using the cookie vulnerability in 2014.
