Disclosure context

About worldleaks

Based on the limited available data, worldleaks is a recently emerged ransomware group that was first observed in May 2025 and appears to be primarily financially motivated, having claimed 134 victims in a relatively short timeframe since its emergence. The group's origin and organizational structure remain unclear, with no publicly documented information from major cybersecurity firms or law enforcement agencies regarding their country of origin, potential affiliations, or operational model. Their targeting patterns indicate a focus on English-speaking countries, particularly the United States, United Kingdom, and Canada, with additional activity observed in Germany and Japan, while their sector targeting shows a preference for healthcare, technology, manufacturing, and consumer services organizations. Due to the group's recent emergence and limited public documentation by established threat intelligence sources, specific details about their attack methodologies, encryption techniques, extortion tactics, and notable campaigns have not yet been comprehensively analyzed or reported by organizations such as CISA, FBI, or major cybersecurity research firms. The group appears to remain active as of the most recent observations, though comprehensive threat intelligence profiling awaits further analysis and documentation by established cybersecurity authorities. The group has been linked to 155 public disclosures across our corpus. First observed on a leak site on May 18, 2025; most recent post May 12, 2026. The operation is currently active.

Timeline of this disclosure

March 20, 2026TSN Co., Ltd. listed by worldleakson the group's public leak site

Sector and geography

This disclosure adds to ransomware activity in the Not Found sector, which has 4,859 disclosures indexed across all operators we track. Geographically, TSN Co., Ltd. is reported in Japan, a country with 108 ransomware disclosures in our corpus.

How we know this. Darkfield monitors public ransomware leak sites continuously, archiving every new disclosure and the data later released against the victim. Each entry on this page is sourced from the operator's own publication and cross-checked against complementary OSINT feeds (RansomLook, ransomware.live, RansomWatch). We do not collect or host stolen data — only the metadata, timestamps and screenshots needed to make the public disclosure searchable and accountable. Records here are corrected when the original post is edited, retracted, or merged with another disclosure.

Ransomware victim disclosure

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株式会社ティーエスエヌ (TSN Co., Ltd.)

listed as TSN Co., Ltd. · Claimed by worldleaks · listed 2 months ago

Age

since listed · data leaked

Status timeline

Listed
Mar 20, 2026
Data leaked

At a glance

Group: worldleaks
Status: Data leaked
Country: Japan
Sector: Not Found
Listed on leak site: Mar 20, 2026

About the victim

AI dossier — public-source company profile

TSN Co., Ltd. (株式会社ティーエスエヌ) is a Japanese creative services company founded in 1968, headquartered in Tennoji, Osaka, with a branch in Minato, Tokyo. The company provides end-to-end creative solutions—from planning and proposal through production—and also operates a branded desk calendar sales service called 'Calepro'.

Industry: Creative Services & Print Production
Address: 大阪府大阪市天王寺区味原町13-11-2 味原トータルライフ4階 (Osaka HQ); 東京都港区芝5-31-10 サンシャインビル6階 (Tokyo Branch)
Founded: 1968

Attack summary

Severity: medium — Data is listed as published rather than merely announced, suggesting confirmed exfiltration, but no details on data type, volume, or sensitivity are available from the leak post, and the company appears to be a small creative/print services firm without obvious regulated-data holdings.

The worldleaks ransomware group has claimed an attack against TSN Co., Ltd. and lists the disclosure status as data_published, indicating exfiltrated data has been released; however, the leak post contains no specific details on the nature or volume of data involved.

medium

Original description

AI-summarised, not from the leak post

N/A

Sources

Victim sitewww.tsn-net.co.jp
Leak posthttps://worldleaksartrjm3c6vasllvgacbi5u3mgzkluehrzhk2jz4taufuid.onion/companies/8506335009

Source

Indexed 2 months ago

This page surfaces a public ransomware disclosure indexed by Darkfield. Original posts come from the operator's own leak site; we cross-check against ransomware.live, RansomLook and RansomWatch where applicable. Share this URL freely.