After a number of Nintendo account holders began reporting unauthorised log-ins last weekend, Nintendo began investigating for a potential security breach. At this point in time, it looks like up to 160,000 Nintendo accounts have been impacted so far, although Nintendo says the leak did not come from its side.
The investigation is still going, but in the meantime, Nintendo says that there is “currently no evidence pointing towards a breach of Nintendo's databases, servers or services”. With that said, Nintendo is disabling the ability to log in to a Nintendo account using a Nintendo Network ID (NNID), a system that was used back in the 3DS and Wii U era.
Nintendo is going to begin contacting affected users with a notice to change their passwords. Nintendo also strongly encourages Nintendo Account holders to go into their security settings and activate two factor authentication (2FA) to avoid unauthorised log-ins.
Nintendo “will not reveal more information” about methods people are using to gain unauthorised access to accounts to deter further attempts.
KitGuru Says: Either there was a massively successful phishing scam targeting Nintendo users at some point, or something fishy is going on. Hopefully Nintendo's investigation will reveal the answers soon enough as 160,000 unauthorised log-in attempts is certainly cause for concern.