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Sincere Corporation

thegentlemen

This record tracks a ransomware attack claimed by the thegentlemen group against Sincere Corporation. It collects the publicly disclosed attack details — sector, location and timeline — as published on the operator's leak site and indexed by Breach House.

Window Zero

EXPOSURE GAP

Window Zero is the time the breach stayed in the open before anyone said so — the gap between when the attack was first discovered on the operator's leak site (t1) and when it was publicly disclosed (t2). The wider this window, the longer victims, staff and customers were exposed with no warning.

223days open
t1 · Published t2 · Pending
Jan 20, 2026Not disclosed yet
Country
Japan
Business Category
Services
Employees
+1000
Discovered
2026-01-21
Published
January 20, 2026
Disclosed / Notified
Not disclosed yet
Victim ID
kq2OS0XSET1l

Attack Summary

Sincerehq.com SINCERE Corporation is a Japanese environmental services company operating under the philosophy of "Symbiosis with Nature," offering "one-stop" solutions in waste management and building maintenance across four main segments: Resource Cycling, Recycling Business, Environmental Improvement and Building Maintenance, and Environmental Consulting. Established in 1969, the company contributes to Japan's circular economy with nationwide operations, including major facilities in Shinagawa and Yokohama.

Leak Screenshots

SAMPLE

Proof-of-breach screenshots the operator posted from the stolen data. Previews are redacted and locked — the originals are available on HaveIBeenRansom.

file_tree.png
finance_2024.xlsx
passport_scan.jpg
contract_signed.pdf
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Dark Web Exposure

Findings for sincerehq.com — indexed by HaveIBeenRansom.
0
found in Infostealer logs
17
found in Traditional breaches
0
found in Ransomware leaks
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Peatix_BF.7z
B F R e p o V 3 F i l e s · breach
••• emails
Leak volumes are locked
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