NEWS
1-6-2 Marunouchi, Chiyoda-ku, Tokyo 100-8246 Japan

October 23, 2023

Completion of Internal and Third-Party Investigations regarding unauthorized accessto our corporate servers (announced on August 23)
Zeon Corporation
On August 23, 2023, we posted a notice on our website regarding an incident involving unauthorized access to our corporate
servers by a third party and the possibility that it may have led to the leakage of certain personal information under ourmanagement.
Both our internal investigation and a third-party investigation by a cybersecurity firm that had been in process since our previous
notice have now been completed, and the results are provided below.
We sincerely apologize for any inconvenience or concern this incident may have caused to those whose information may havebeen affected.
Results of the Third-Party Investigation
As we reported in our previous notice, any damage from unauthorized access was limited to the possibility that some personal
information stored in our account management system (directory server) may have been leaked to external parties, and wehave reconfirmed that there were no signs of a breach in any of our other corporate servers.
Details of Personal Information that May Have Been Leaked to External Parties (total of 13,434 records related to (1) to (2)below)(1) Information on customers and business partners registered in the group addresses managed by the Company (8,236
addresses)
E-mail addresses and personal names of customers and suppliers and related domains
We sent an e-mail on August 24, 2023 to all those whose personal information may have been leaked
to further inform them of this matter. (Anyone who did not receive an e-mail notification can assume
that they have not been affected.)
Please note that our account management system (directory server) only contains the e-mail addresses and names of customers
and suppliers and related domains. There is no possibility of any other information being leaked.
(2) Account information of employees of the Company and its Group companies, as well as employees of subcontractors(5,198 accounts)
User IDs issued by the Company and its Group companies
E-mail addresses issued by the Company and its Group companies
Name (in Japanese characters)
Name (in alphabet)Company name
Department name
Organization code
Employee number
Phone number
Note that any personal information that has been exposed may be misused to distribute spam or conduct phishing via e-mail.
Please take every reasonable precaution.

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NEWS
1-6-2 Marunouchi, Chiyoda-ku, Tokyo 100-8246 Japan

Our Response(1) Reporting to administrative organs
Upon receiving the results of the third-party investigation, a final report of this incident was submitted to the Ministry ofEconomy, Trade and Industry and the Personal Information Protection Commission of Japan on October 16, 2023.
(2) Response to all those whose personal information may have been leaked
All those whose personal information may have been leaked have been notified individually by e-mail, as mentioned above.
We have reported to and are consulting with the administrative organs regarding the details of the cyberattack, including thepossible method of attack, and we are also cooperating with the administrative organs regarding the information we aredisclosing, including this notice.
We are taking this situation very seriously, and with the assistance of an external cybersecurity firm, we will endeavor toestablish an even more robust information security system to prevent any recurrence.
We deeply regret any concern this incident may have caused and will spare no effort to prevent it from happening again.
For inquiries regarding this matter, please contact:
Zeon Corporation Secretariat of the Cyber Security Committee
E-mail: Contact-CyberSecurityCommittee@zeon.co.jp

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