Dwango: several unauthorized logins to Niconico used passwords leaked from other services

1. 2021-12-10

   It announced that it had detected several logins that did not seem to be by the account owners. It said it would block the old passwords of accounts confirmed to be hijacked and send guidance to their registered email addresses. [1] [2]

If an account is logged into without authorization, the points could be used or bought, the registered email address or password changed, videos or comments posted, and registered data with limited visibility, such as gender and birth date, viewed. The attacker appears to have used email and password pairs leaked from other services. [1] [2]