Phishers target Mastercard users in Japan by sending spammed email that instructs recipients to update their Mastercard accounts online. The message informs users that Mastercard supposedly updated their online system for security purposes. A link that leads to a Mastercard page where users can update their account is provided. However, the said link is actually the phishing site. This phishing scheme targets Japanese users as the account information page/phishing page uses Japanese characters for input:
As with other phishing schemes, the phishing site asks for the intended victim's personal information such as name on the card, debit card or credit card numbers, expiration date, card type, verification code, card issuing bank, and ATM pin.
Mastercard, or any other financial institution, will never send you email unless you signed up for alerts like these. For security purposes, it's always good to check and re-check information by going to the official institution's website or calling their customer service numbers.