Security Incident at Our Company (Second Report)

May 21, 2025
Resonac Holdings Corporation

Resonac Corporation (hereinafter referred to as "our company") announced on our website on May 20, 2025, the first report regarding the security incident that occurred at our company. Our emergency response headquarters has been investigating the scope of impact and working diligently to restore systems and resume normal operations as soon as possible.
We sincerely apologize for the great concern and inconvenience caused to our business partners and all related parties.
It will take some time to fully assess the damage and complete the recovery, but we would like to report the current known details below as of 9:00 AM, May 21.

1. Incident Overview
In the early hours of Tuesday, May 20, an external attack was detected on some of our company's and our group's servers. Subsequently, ransomware infection was confirmed. We immediately began an investigation with the cooperation of external experts and established an emergency response headquarters to promptly address the situation.
Measures such as network isolation were implemented, leading to partial system outages within our company and group, affecting business operations.

2. Current Status and Future Actions
As of 8:00 AM on Wednesday, May 21, we are taking measures to prevent further damage while working on system protection and recovery.
Additionally, we are proceeding with filing reports to the police and coordinating with relevant government agencies, aiming to minimize inconvenience to affected parties.
At this stage, partial business recovery is expected by Monday, May 26.
Furthermore, no leakage of personal information related to our company, group, or business partners has been confirmed at this time.
The impact of this incident on our financial performance is still under assessment. If it is found to have a significant effect, we will promptly disclose the details.
We sincerely apologize once again for the inconvenience and disruption caused to our business partners.