Was SFA Engineering hit by ransomware?

SFA Engineering was listed by the Underground ransomware operation (South Korea), 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 Underground ransomware group?

Underground 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 SFA Engineering breach?

Underground published data attributed to SFA Engineering (~2.3 TB). Darkfield captured the leak post and a screenshot of the listing.

Ransomware victim disclosure

← All victims

SFA Engineering

Claimed by Underground · listed 11 months ago

2.3 TB

Data size

$1.7B

Ransom

demanded

11m

Age

since listed · data leaked

Status timeline

ListedAug 15, 2025
Data leakeddate unknown

At a glance

Group: Underground
Status: Data leaked
Country: South Korea
Sector: Technology
Listed on leak site: Aug 15, 2025
Data size: 2.3 TB
Ransom demanded: $1.7B
Estimated revenue: $1.7B

About the victim

AI dossier — public-source company profile

SFA Engineering is a South Korean engineering company. Limited publicly available information is available from the clearnet domain sfa.co.kr.

Industry: Engineering & Design

Attack summary

Severity: high — Confirmed data exfiltration of 2.3 TB with public disclosure; extremely high ransom demand ($1.7B) suggests significant data sensitivity or operational criticality, though specific data types are not detailed in the post.

The Underground group claims to have exfiltrated 2.3 TB of data from SFA Engineering. The group is demanding $1.7B ransom and has published the data on their leak site.

high

Data the group says was taken

AI dossier — extracted from the leak post

company records
business documents
technical files

What the group claims

Revenue: $1.7 Billion Type: Industry Size: 2,3 TBytes

The leak post

captured from the group's site

All data | Underground store Data Announcements All data Afghanistan Albania Algeria American Samoa Andorra Angola Anguilla Antigua and Barbuda Argentina Armenia Aruba Australia Austria Azerbaijan Bahamas Bahrain Bangladesh Barbados Belarus Belgium Belize Benin Bermuda Bhutan Bolivia Bonaire, Sint Eustatius and Saba Bosnia and Herzegovina Botswana Brazil British Virgin Islands Brunei Darussalam Bulgaria Burkina Faso Burundi Cambodia Cameroon Canada Cape Verde Cayman Islands Central African Republic Chad Chile China Colombia Comoros Congo Congo, Democratic Republic Cook Islands Costa Rica Côte d`Ivoire Croatia Cuba Curaçao Cyprus Czech Republic Denmark Djibouti Dominica Dominican Republic East Timor Ecuador Egypt El Salvador Equatorial Guinea Eritrea Estonia Ethiopia Falkland Islands Faroe Islands Fiji Finland France French Guiana French Polynesia Gabon Gambia Georgia Germany Ghana Gibraltar Greece Greenland Grenada Guadeloupe Guam Guatemala Guinea Guinea-Bissau Guyana Haiti Honduras Hong Kong Hungary Iceland India Indonesia Iran Iraq Ireland Isle of Man Israel Italy Jamaica Japan Jordan Kazakhstan Kenya Kiribati Kuwait Kyrgyzstan Laos Latvia Lebanon Lesotho Liberia Libya Liechtenst…

Sources

Source

Indexed 11 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.

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 Underground

Underground is a relatively new ransomware group that emerged in May 2024, primarily motivated by financial gain through extortion operations targeting organizations across multiple sectors. The group's origin and affiliations remain largely undocumented in public threat intelligence reporting, with no confirmed details about their country of origin or whether they operate as an independent entity or through a Ransomware-as-a-Service model. Based on the limited public information available, Underground has demonstrated a preference for targeting technology, healthcare, business services, manufacturing, and agriculture sectors, with their attacks concentrated primarily in the United States, Canada, South Korea, Germany, and Taiwan. The group's specific attack methodologies, initial access vectors, and technical capabilities have not been extensively documented in publicly available threat intelligence reports from major security firms or government agencies. With only 26 known victims since their emergence in May 2024, Underground represents a smaller-scale operation compared to established ransomware groups, though their cross-sector targeting approach indicates opportunistic victim selection rather than specialized industry focus. Given the recent emergence of this group and limited public reporting, Underground appears to remain active but operates at a relatively low profile compared to more established ransomware families. The group has been linked to 26 public disclosures across our corpus. First observed on a leak site on May 1, 2024; most recent post August 15, 2025. The operation is currently inactive.

Timeline of this disclosure

August 15, 2025SFA Engineering listed by Undergroundon the group's public leak site

Data size: 2.3 TB
Ransom demanded: $1.7B

Other recent disclosures by Underground

Underground has been linked to 26 public victims on Darkfield. A sample of the most recent:

See the full Underground 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, SFA Engineering is reported in South Korea, a country with 48 ransomware disclosures in our corpus.

If your organisation is affected

A listing by Underground means SFA Engineering 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, KrCERT/CC (South Korea), as required for your jurisdiction.
Monitor for the data appearing on Underground'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.