Disclosure context

About d4rk4rmy

d4rk4rmy is a recently emerged ransomware group that was first observed in July 2025, operating with apparent financial motivations based on their targeting of high-value sectors including financial services and technology organizations. With only 18 documented victims to date, the group appears to be in its early operational phase, demonstrating a geographically diverse targeting approach across the United States, Taiwan, Brazil, Poland, and Monaco, with particular focus on financially lucrative sectors such as financial services, technology, transportation and logistics, and hospitality and tourism industries. Given the group's recent emergence and limited public documentation from established threat intelligence sources, specific details regarding their country of origin, operational structure, attack methodologies, encryption techniques, and whether they operate as a Ransomware-as-a-Service model remain largely undetermined by major cybersecurity organizations such as CISA, FBI, or prominent security research firms. The group's current operational status appears active based on the recent timeline of their emergence, though comprehensive analysis of their capabilities, notable campaigns, and potential law enforcement actions is limited due to insufficient publicly available intelligence from authoritative sources. The group has been linked to 18 public disclosures across our corpus. First observed on a leak site on July 7, 2025; most recent post August 16, 2025. The operation is currently inactive.

Timeline of this disclosure

August 7, 2025MIZUHA FINANCIAL GROUP listed by d4rk4rmyon the group's public leak site

Sector and geography

This disclosure adds to ransomware activity in the Financial Services sector, which has 516 disclosures indexed across all operators we track. Geographically, MIZUHA FINANCIAL GROUP 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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MIZUHA FINANCIAL GROUP

Claimed by d4rk4rmy · listed 10 months ago

Age

since listed · data leaked

Status timeline

Listed
Aug 7, 2025
Data leaked

At a glance

Group: d4rk4rmy
Status: Data leaked
Country: Japan
Sector: Financial Services
Listed on leak site: Aug 7, 2025

About the victim

AI dossier — public-source company profile

Mizuho Financial Group is one of the world's largest financial institutions, formed in 2002 from the merger of Dai-Ichi Kangyo Bank, Fuji Bank, and the Industrial Bank of Japan. It operates globally through subsidiaries including Mizuho Bank, Mizuho Trust & Banking, and Mizuho Securities, providing corporate finance, capital markets, asset management, and institutional services across Asia, Americas, Europe, Middle East, and Africa.

Industry: Banking & Financial Services
Address: Tokyo, Japan (Head Office)
Employees: 70000+
Founded: 2002

Attack summary

Severity: medium — Disclosure status is 'data_published' against a systemically important global financial institution, but the leak post excerpt provided contains no substantive detail of exfiltrated data, proof files, or attack scope. Risk is moderated by lack of published evidence in the available text; however, any confirmed breach of a major bank poses regulatory and operational concern.

d4rk4rmy claims to have accessed Mizuho Financial Group's systems. The group post truncates at company history without detailing specific data exfiltration, encryption claims, or proof of access.

medium

What the group claims

https://www.mizuhogroup.com In 2002, Dai–Ichi Kangyo Bank, Fuji Bank, and the Industrial Bank of Japan merged to form the Mizuho Financial Group. Since then, Mizuho has developed an extensive network in Asia and the rest of the world through a consistent…

Sources

Victim sitewww.mizuhogroup.com

Source

Indexed 10 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.