Was Unimicron hit by ransomware?

Unimicron was listed by the Sarcoma ransomware operation (Taiwan), 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 Sarcoma ransomware group?

Sarcoma 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 Unimicron breach?

Sarcoma published data attributed to Unimicron (~377 GB). Darkfield captured the leak post and a screenshot of the listing.

Ransomware victim disclosure

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Unimicron

Claimed by Sarcoma · listed 1 year ago

377 GB

Data size

17m

Age

since listed · data leaked

Status timeline

ListedFeb 11, 2025
Data leakeddate unknown

At a glance

Group: Sarcoma
Status: Data leaked
Country: Taiwan
Sector: Technology
Listed on leak site: Feb 11, 2025
Data size: 377 GB

About the victim

AI dossier — public-source company profile

Unimicron is a major global manufacturer of high-density interconnect (HDI) printed circuit boards and carriers for advanced mobile phones and semiconductors. Operating three strategic business units (PCB, Carrier, and IC Test), the company manufactures from multiple facilities across Taiwan, China, Germany, and Japan to serve OEM and component customers worldwide.

Industry: Printed Circuit Boards (PCB) & Semiconductor Carrier Manufacturing
Address: Manufacturing locations in Taiwan (Taoyuan, Hsinchu), Shenzhen, Huangshi, Kunshan, Suzhou; also Germany and Japan; offices in America, Europe, and Asia

Attack summary

Severity: high — Confirmed exfiltration of 377 GB from a critical semiconductor supply-chain manufacturer; data includes SQL databases (likely containing proprietary designs, customer information, and operational records). Unimicron supplies major mobile phone manufacturers, making this a significant business intelligence and IP threat.

The Sarcoma group claims to have exfiltrated 377 GB of data from Unimicron, including files and SQL databases. The post does not explicitly state encryption or operational disruption.

high

Data the group says was taken

AI dossier — extracted from the leak post

Files
SQL databases

What the group claims

Unimicron Made up of three strategic business units (SBU), namely PCB SBU, Carrier SBU, and IC Test SBU, Unimicron is currently among the top PCB and carrier manufactures in the world and a major supplier of HDI PCBs and carrier for world advanced mobile phones. Manufacturing bases are mainly set in Taiwan (Taoyuan, Hsinchu), Shenzhen of South China, Huangshi of Central China, and Kunshan and Suzhou of East China-Plants in China specialize in mass production, while in Taiwan provide high-end products to serve the market. In addition, to instantly respond to the demands of customers, besides establishing sales departments and representative offices in America, Europe, and Asia, there are also manufacturing bases in Germany and Japan to serve the customers there.Geo: Taiwan - Leak size: 377 GB Archive - Contains: Files, SQL

Sources

Victim siteunimicron.com

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 Sarcoma

Sarcoma is a relatively new ransomware group that emerged in October 2024, operating with apparent financial motivations and demonstrating a broad international targeting approach with at least 140 documented victims across multiple countries and industry sectors. The group's origin and affiliations remain unclear due to its recent emergence, with no publicly documented connections to established ransomware families or confirmation of whether they operate as an independent entity or through a Ransomware-as-a-Service model. Limited public information is available regarding Sarcoma's specific attack methodologies, initial access vectors, or technical capabilities, though their targeting patterns suggest opportunistic rather than highly selective victim selection across diverse industries including manufacturing, business services, agriculture and food production, and technology sectors. The group has shown a particular focus on victims in the United States while also maintaining operations against targets in Italy, Canada, Germany, and Australia, though no specific high-profile attacks or record ransom demands have been publicly documented by major security firms or law enforcement agencies. Given the group's recent emergence in late 2024, Sarcoma appears to remain active with no reported law enforcement disruptions or confirmed rebranding activities at this time. The group has been linked to 150 public disclosures across our corpus. First observed on a leak site on October 9, 2024; most recent post May 12, 2026. The operation is currently active.

Also tracked as: Sarcoma Ransomware Group.

Timeline of this disclosure

February 11, 2025Unimicron listed by Sarcomaon the group's public leak site

Data size: 377 GB

Other recent disclosures by Sarcoma

Sarcoma has been linked to 150 public victims on Darkfield. A sample of the most recent:

See the full Sarcoma dossier →

Sector and geography

This disclosure adds to ransomware activity in the Technology sector, which has 3,549 disclosures indexed across all operators we track. Geographically, Unimicron is reported in Taiwan, a country with 71 ransomware disclosures in our corpus.

If your organisation is affected

A listing by Sarcoma means Unimicron 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.
Monitor for the data appearing on Sarcoma'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.