KOIKE Sanso Kogoyo Co. Ltd.
exitium listed this organization on its leak site on Oct 10, 2026.
- Listing date
- Oct 10, 2026
- Attack date
- Oct 10, 2026
Listing text
Website: koike-japan.com You have time until Tuesday(10.13.2026). If you wouldn't contact us we will start selling data. We have 5.8 TB of data: agreements confidential data correspondence files all customers and clients data engineering drawings AND MUCH MORE... Contact us until your time runs out.
About the group
exitium posted its first listing on Mar 17, 2026 and has listed 6 organizations to date.
Exitium is a data extortion group first observed in early 2026, operating a Tor-based double extortion site and targeting victims via bulk data exfiltration followed by public naming-and-shaming, with known victims including a Brazilian agro-industrial firm and a US county appraisal district.
Learning center
What does this listing mean?
Ransomware groups move data out of the organization before encrypting systems and threaten to publish it if the ransom is not paid. This method is called double extortion.
The listing shows that the group claims to have targeted the organization. Whether the data was published is shown by the later status of the listing.
What should you do if your organization is listed on a leak site?
- Record the listing and any published sample files; do not visit the leak site from the corporate network.
- Isolate affected systems and preserve logs without deleting them.
- Determine which data left the organization; if personal data is involved, review notification obligations with your legal team.
- Make any decision about the ransom demand together with legal, management and incident response.
- Do not bring systems back online before the attacker’s entry point is closed.
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