Skip to main content
Darkfield

Ransomware victim disclosure

← All victims

Natsume Tax Accountant Corporation

Claimed by 8Base · listed 2 years ago

25m
Age
since listed · data leaked

Status timeline

  1. ListedMay 27, 2024
  2. Data leakeddate unknown

At a glance

Group
8Base
Status
Data leaked
Country
Japan
Sector
Business Services
Listed on leak site
May 27, 2024

About the victim

AI dossier — public-source company profile

Natsume Tax Accountant Corporation is a tax accounting firm located in Shinagawa, Tokyo, Japan. They provide tax return preparation, tax advisory services, and accounting support to corporate and individual clients.

Industry
Tax Accounting & Advisory Services
Address
Shinagawa, Tokyo, Japan

Attack summary

Severity: medium — Tax accounting firms handle sensitive financial and personal information including PII and tax documents. Data published status indicates exfiltration occurred, but no proof files are described in the post and no specific data inventory is detailed. The absence of ransom demand and minimal post content suggest this may be a listing announcement rather than an active extortion campaign.

8Base claims to have compromised Natsume Tax Accountant Corporation. The leak post provides no specific details on data exfiltration, encryption, or operational impact.

medium

Data the group says was taken

AI dossier — extracted from the leak post
  • Tax records
  • Client financial information
  • Tax return data

What the group claims

We work diligently, reliably and sensitively as your trusted partner, paying special attention to tax returns and tax advice.Partnership with everyone is the basis of our daily workThis is a tax accounting department located in Shinagawa.https://www.natsumeoffice.or.jp/

Sources

Source

Indexed 2 years 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.

Is this your supplier? Your competitor? You?

Pro plans monitor your domain, corporate emails, and crypto wallets across every new ransomware leak-site post, breach dump and Telegram callout — alerts within 5 minutes.

Disclosure context

About 8Base

8Base is a ransomware group that emerged in May 2023, operating with primarily financial motivations and demonstrating a rapid escalation in activity with 458 documented victims across multiple sectors. The group's origin and specific affiliations remain largely undocumented by major security agencies, though their operational patterns suggest they function as an independent ransomware operation targeting predominantly Western markets. Based on publicly available victim data, 8Base appears to focus on opportunistic attacks against business services and manufacturing sectors, with the United States representing their primary target geography, followed by France, Brazil, Italy, and the United Kingdom, indicating a preference for developed economies with established digital infrastructure. The group has notably impacted healthcare and technology sectors alongside their primary business services focus, suggesting a broad targeting approach rather than sector-specific specialization. Given the group's recent emergence in 2023 and continued victim accumulation across diverse geographic and sectoral targets, 8Base appears to remain active as of current reporting periods, though detailed technical methodologies, specific attack vectors, and notable high-profile campaigns have not been extensively documented in public threat intelligence reporting from major security agencies. The group has been linked to 458 public disclosures across our corpus. First observed on a leak site on May 23, 2023; most recent post February 1, 2025. The operation is currently inactive.

Timeline of this disclosure

  • May 27, 2024Natsume Tax Accountant Corporation listed by 8Baseon the group's public leak site

Other recent disclosures by 8Base

8Base has been linked to 458 public victims on Darkfield. A sample of the most recent:

See the full 8Base dossier →

Sector and geography

This disclosure adds to ransomware activity in the Business Services sector, which has 3,796 disclosures indexed across all operators we track. Geographically, Natsume Tax Accountant Corporation is reported in Japan, a country with 220 ransomware disclosures in our corpus.

If your organisation is affected

A listing by 8Base means Natsume Tax Accountant Corporation appeared on a ransomware extortion site and data attributed to it has been published. If this is your organisation, or a supplier you depend on, the priority is to confirm the intrusion and contain it before the window to act closes.

  • Engage your incident-response team and preserve forensic evidence before remediating — do not wipe affected systems first.
  • Force a password reset and revoke active sessions for exposed accounts; rotate any credentials, API keys or certificates that may have been in the stolen data.
  • Assess regulatory notification duties (GDPR, NIS2, sector regulators) — many carry a 72-hour reporting clock from awareness.
  • Report the incident to your national CERT, JPCERT/CC (Japan), as required for your jurisdiction.
  • Monitor for the data appearing on 8Base's leak site and across paste and breach channels, and brief downstream partners who may be exposed through you.

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.