Was National Defense Corp hit by ransomware?

National Defense Corp was listed by the Interlock ransomware operation (United States), 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 Interlock ransomware group?

Interlock 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 National Defense Corp breach?

Interlock published data attributed to National Defense Corp. Darkfield captured the leak post and a screenshot of the listing.

Ransomware victim disclosure

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National Defense Corporation

listed as National Defense Corp · Claimed by Interlock · listed 1 year ago

15m

Age

since listed · data leaked

Status timeline

ListedMar 29, 2025
Data leakeddate unknown

At a glance

Group: Interlock
Status: Data leaked
Country: United States
Sector: Public Sector
Listed on leak site: Mar 29, 2025

About the victim

AI dossier — public-source company profile

National Defense Corporation (NDC), a wholly owned subsidiary of National Presto Industries Inc., is a U.S. defense manufacturer headquartered in Eau Claire, Wisconsin. Restructured in 2014, NDC consolidates five defense-focused companies: AMTEC Corporation (40mm grenade ammunition and fuzing), Amron (medium-caliber cartridge cases), Tech Ord (detonators and military energetic devices), Spectra Technologies (ordnance manufacturing and warheads), and Woodlawn Manufacturing (precision metal parts for defense and aerospace). NDC serves as a prime contractor to the U.S. Army and international allies.

Industry: Defense Manufacturing – Ammunition, Explosives & Military Ordnance
Address: Eau Claire, Wisconsin, United States
Founded: 2014

Attack summary

Severity: critical — National Defense Corporation is a U.S. Department of Defense contractor with active military contracts worth up to $826.8 million, manufacturing lethal ordnance (40mm grenade ammunition, detonators, explosives, warheads) for the U.S. Army and international allies. Exfiltration of any data from a defense contractor of this sensitivity poses significant national security and operational risk, regardless of the specific data type confirmed in the post. The company manufactures primary explosives an

The Interlock group claims to have exfiltrated data from National Defense Corporation, a U.S. defense contractor specializing in military ammunition, explosives, and ordnance manufacturing. The leak post provides no specific details on the scope, type, or sensitivity of exfiltrated data.

critical

Data the group says was taken

AI dossier — extracted from the leak post

Defense contractor records
Military contract documentation
Manufacturing specifications
Customer/supplier information

What the group claims

AMTEC is a manufacturer of lethal and non-lethal ammunition, explosives, and cartridges for military and law enforcement use. Globally, AMTEC is the largest volume producer of 40mm Grenade Ammunition and Fuzing. Their capabilities include precision assembly, explosive load, assemble and pack, metal forming and plating, and primary explosive manufacturing. The company is headquartered in Janesville, Wisconsin.

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 Interlock

Interlock is a recently emerged ransomware group that began operations in October 2024, primarily motivated by financial gain through extortion activities targeting organizations across multiple sectors. The group's country of origin and potential affiliations remain unclear given their recent emergence, with insufficient public documentation to determine whether they operate as an independent entity or under a Ransomware-as-a-Service model. Limited public information exists regarding their specific attack methodologies, initial access vectors, or encryption techniques, as major cybersecurity firms and law enforcement agencies have not yet published comprehensive technical analyses of their operations. Since beginning operations, Interlock has reportedly compromised approximately 100 victims, with their targeting primarily focused on organizations in English-speaking countries including the United States, Canada, United Kingdom, and Australia, as well as Italy, while demonstrating a preference for attacking education, manufacturing, healthcare, and public sector entities. The group remains active as of late 2024, though comprehensive threat intelligence profiles from established security research organizations have not yet been published due to the group's recent emergence in the threat landscape. The group has been linked to 114 public disclosures across our corpus. First observed on a leak site on October 13, 2024; most recent post July 10, 2026. The operation is currently active.

Timeline of this disclosure

March 29, 2025National Defense Corp listed by Interlockon the group's public leak site

Other recent disclosures by Interlock

Interlock has been linked to 114 public victims on Darkfield. A sample of the most recent:

See the full Interlock dossier →

Sector and geography

This disclosure adds to ransomware activity in the Public Sector sector, which has 466 disclosures indexed across all operators we track. Geographically, National Defense Corp is reported in United States, a country with 11,033 ransomware disclosures in our corpus.

If your organisation is affected

A listing by Interlock means National Defense Corp 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, CISA (United States), as required for your jurisdiction.
Monitor for the data appearing on Interlock'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.