Red Ark Laboratories LLC (the Company) reviewed the unauthorized access incident involving Sakura Internet Inc., based on Sakura Internet’s public notice dated August 19, 2026 (“Notice regarding unauthorized access to our systems (Second Report)”).
Although we have not received any communication from Sakura Internet indicating that member IDs managed by the Company were leaked, Sakura Internet’s investigation results have suggested a possible access to hashed password information stored in its sales management system. Therefore, as a precautionary measure, we changed the passwords for all member IDs managed by the Company (including those registered under our customers’ names).
In general, “reversing” hashed password data back to plaintext is difficult. However, depending on the hashing method (algorithm), whether a salt is used, and the computational cost, attackers may still be able to attempt offline guessing (e.g., dictionary attacks) against leaked hashes. Taking these possibilities into account, we implemented preventive password changes.
Reference: Sakura Internet Inc. public notice
https://www.sakura.ad.jp/corporate/information/newsreleases/2026/08/19/1968225633/
The Company will continue to monitor the situation and update this information as necessary.