Was MinebeaMitsumi Inc hit by ransomware?

MinebeaMitsumi Inc was listed by the Cicada3301 ransomware operation (Japan), and stolen data was published on the group's leak site. Darkfield tracks this disclosure with the original leak post, screenshot and group context.

Who is the Cicada3301 ransomware group?

Cicada3301 is a ransomware operator tracked by Darkfield. See the full operator dossier for its known victims, sectors targeted, IOCs and leak-site infrastructure.

What data was leaked in the MinebeaMitsumi Inc breach?

Cicada3301 published data attributed to MinebeaMitsumi Inc (~3.2 TB). Darkfield captured the leak post and a screenshot of the listing.

Ransomware victim disclosure

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MinebeaMitsumi Inc

Claimed by Cicada3301 · listed 1 year ago

3.2 TB

Data size

15m

Age

since listed · data leaked

Status timeline

ListedMar 22, 2025
Data leakeddate unknown

At a glance

Group: Cicada3301
Status: Data leaked
Country: Japan
Sector: Manufacturing
Listed on leak site: Mar 22, 2025
Data size: 3.2 TB

About the victim

AI dossier — public-source company profile

MinebeaMitsumi Inc is a Japanese multinational manufacturer of precision mechanical and electronic components, including bearings, semiconductors, sensors, and IoT devices. The company operates globally with manufacturing and development facilities, serving automotive, industrial machinery, healthcare, and information technology sectors.

Industry: Precision Manufacturing & Electronic Components

Attack summary

Severity: high — Confirmed exfiltration of 3.2 TB of data from a major multinational manufacturer with global supply-chain relevance; data already published. Scale and presumed sensitivity of corporate/technical data from a precision component supplier warrants high severity despite lack of specific data category detail in the post.

Cicada3301 claims to have exfiltrated 3.2 TB of data from MinebeaMitsumi. The group has published the data; no specific details on data categories or operational impact are provided in the available post excerpt.

high

Data the group says was taken

AI dossier — extracted from the leak post

corporate records
technical documentation
business data

What the group claims

Status: 20d 19h 5m 16s - Size Data: 3.2 TB

Sources

Source

Indexed 1 year 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.

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Disclosure context

About Cicada3301

Cicada3301 is a recently emerged ransomware group that began operations in June 2024, primarily motivated by financial gain through extortion activities targeting organizations across multiple sectors. The group's origin and affiliations remain largely undocumented in public threat intelligence reporting, with limited information available regarding their operational structure or potential connections to other cybercriminal organizations. Based on observed targeting patterns, Cicada3301 has demonstrated a preference for attacking business services, technology, manufacturing, and financial sector organizations, with their operations concentrated primarily in English-speaking countries including the United States, United Kingdom, and Canada, as well as extending to Spain and Singapore. The group has successfully compromised approximately 75 known victims since their emergence, though specific details regarding their attack methodologies, initial access vectors, encryption techniques, and extortion tactics have not been extensively documented in publicly available threat intelligence reports from major cybersecurity firms or government agencies. Given the limited public documentation available from CISA, FBI, Mandiant, or other reputable security researchers, the group's current operational status, technical capabilities, and specific attack infrastructure remain largely uncharacterized in open-source intelligence reporting. As of the most recent observations, Cicada3301 appears to remain active in conducting ransomware operations, though comprehensive analysis of their tactics, techniques, and procedures awaits more detailed public reporting from established threat intelligence sources. The group has been linked to 75 public disclosures across our corpus. First observed on a leak site on June 20, 2024; most recent post September 4, 2025. The operation is currently inactive.

Timeline of this disclosure

March 22, 2025MinebeaMitsumi Inc listed by Cicada3301on the group's public leak site

Data size: 3.2 TB

Other recent disclosures by Cicada3301

Cicada3301 has been linked to 75 public victims on Darkfield. A sample of the most recent:

See the full Cicada3301 dossier →

Sector and geography

This disclosure adds to ransomware activity in the Manufacturing sector, which has 3,681 disclosures indexed across all operators we track. Geographically, MinebeaMitsumi Inc is reported in Japan, a country with 220 ransomware disclosures in our corpus.

If your organisation is affected

A listing by Cicada3301 means MinebeaMitsumi Inc 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 Cicada3301'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.