Cyber Threat Intelligence
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Ransomware Victim Financial Services

MIZUHA FINANCIAL GROUP

Ransomware attack by D4rk4rmy · Disclosed August 7, 2025 · 🇯🇵 Japan

www.mizuhogroup.com

Date Disclosed
Aug 7, 2025
2025
Threat Group
D4rk4rmy
18 total victims
Country
🇯🇵 Japan
Industry
Financial Services

ThreatAI Analysis

Compiled from this incident record and the threat intelligence profile for D4rk4rmy. Figures and technique mappings are quoted from the source data, not inferred.

About the D4rk4rmy group

D4rk4rmy is a ransomware and data extortion group active since at least 2025, targeting financial services, hospitality, technology, and logistics sectors, operating a RaaS model with notable claimed victims including the Monte Carlo casino resort. D4rk4rmy has listed 18 victims since July 2025.

Incident Analysis

MIZUHA FINANCIAL GROUP was targeted by D4rk4rmy ransomware, one of the most active ransomware groups in our database with 18 confirmed victims globally. The attack was disclosed on August 7, 2025, when MIZUHA FINANCIAL GROUP appeared on the group's dark web leak site.

MIZUHA FINANCIAL GROUP is based in Japan , operating in the Financial Services sector. Japan ranks #11 globally for ransomware attacks, with 274 victims in our database.

Sector context: Financial sector organisations are targeted for their access to funds, sensitive financial data, and the reputational damage a public breach can cause. Regulatory requirements also increase recovery costs.

D4rk4rmy typically employs a double extortion model: first exfiltrating sensitive data from the victim's systems, then deploying ransomware to encrypt files. Victims face two simultaneous threats — paying to restore access and paying to prevent publication of stolen data. The group's leak site publishes victim names and exfiltrated data as leverage.

Data source: This incident record is sourced from public ransomware group leak site disclosures aggregated via the ransomware.live API. Disclosure date reflects when the victim was published on the leak site, which may differ from the initial date of compromise. This platform does not publish or link to stolen data. Last data update: Sep 20, 2026 20:00 UTC.

Frequently Asked Questions

Was MIZUHA FINANCIAL GROUP attacked by ransomware?

Yes. MIZUHA FINANCIAL GROUP was listed as a victim of the D4rk4rmy ransomware group on August 7, 2025. The organisation is based in Japan and operates in the Financial Services sector. The disclosure appeared on the group's dark web leak site.

Which ransomware group attacked MIZUHA FINANCIAL GROUP?

MIZUHA FINANCIAL GROUP was attacked by D4rk4rmy ransomware. D4rk4rmy is one of the most active ransomware groups, having claimed 18 victims globally. The group typically employs a double-extortion model: encrypting the victim's files and threatening to publish stolen data.

When did the MIZUHA FINANCIAL GROUP ransomware attack occur?

The ransomware attack on MIZUHA FINANCIAL GROUP was disclosed on August 7, 2025. This date reflects when the victim was published on the threat group's leak site, which may differ from the actual date of initial compromise.

What data was stolen in the MIZUHA FINANCIAL GROUP ransomware attack?

The specific data stolen from MIZUHA FINANCIAL GROUP has not been independently verified by this platform. Ransomware groups typically exfiltrate data before encrypting systems and use the threat of publication to pressure victims. As a Financial Services organisation, MIZUHA FINANCIAL GROUP likely held financial records, client data, and transaction histories.

How can organisations protect against D4rk4rmy attacks?

To defend against D4rk4rmy and similar threat actors, organisations should: maintain regular offline backups tested for restoration; implement network segmentation to limit lateral movement; deploy multi-factor authentication on all remote access; use endpoint detection and response (EDR) tools; conduct regular phishing and security awareness training; and monitor threat intelligence feeds for indicators of compromise (IOCs) associated with active groups.