Personal data belonging to fans of five Pacific League baseball clubs leaked after a third party gained unauthorized access to systems tied to the clubs' official websites, Pacific League Marketing and the six Pacific League clubs said on November 6. The five are the Hokkaido Nippon-Ham Fighters, the Tohoku Rakuten Golden Eagles, the Saitama Seibu Lions, the Chiba Lotte Marines and the Fukuoka SoftBank Hawks. Orix was not affected.
Names, credit card and other payment details, and fan club membership records were not exposed, according to the announcement. No secondary harm from misuse of the leaked data has been confirmed.
More than 13,000 addresses from a mailing tool
The incident splits into two separate breaches. The first was unauthorized access to Arara Message, an outside email delivery service used for breaking-news newsletters. A total of 13,711 email addresses of newsletter subscribers across the five clubs leaked.
Arara gave the first notice of the unauthorized access on October 28, and follow-up investigation confirmed on November 5 that Pacific League clubs were affected.
Intrusion at Chiba Lotte's official site
The second breach hit the Chiba Lotte Marines' official website. On November 4, staff found a page in the site's management system that no one had created. An investigation showed the site had been accessed without authorization on October 30.
A file was downloaded and leaked containing 11,875 email addresses and 37,070 registered nicknames of paying members of the official smartphone site, including former members.
The five clubs have stopped using Arara's email delivery service. The Marines' official site is down for emergency maintenance, and the club is working with an outside specialist investigation firm on the vulnerabilities. There is no estimate yet for when the site will be back.
The league's clubs are not alone in holding fan contact data on outside mailing tools. Sorashido Air and AIRDO said on November 4 that unauthorized access to their email delivery services had leaked personal information, about 490,000 records at Sorashido and 670,000 at AIRDO.