Was MCM Construction hit by ransomware?

MCM Construction was listed by the blacklock 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 blacklock ransomware group?

blacklock 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 MCM Construction breach?

blacklock published data attributed to MCM Construction, around 25 Employees records. Darkfield captured the leak post and a screenshot of the listing.

Ransomware victim disclosure

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MCM Construction

Claimed by Blacklock · listed 1 year ago

25 Employees

Records

$26.1M

Ransom

demanded

13m

Age

since listed · data leaked

Status timeline

ListedMay 30, 2025
Data leakeddate unknown

At a glance

Group: Blacklock
Status: Data leaked
Country: United States
Sector: Construction
Listed on leak site: May 30, 2025
Records: 25 Employees
Ransom demanded: $26.1M
Estimated revenue: $26.1M

About the victim

AI dossier — public-source company profile

MCM Construction is a bridge and infrastructure construction company based in North Highlands, California, with 40+ years of operational history. The company specializes in building critical structures including bridges, overpasses, and interconnectors throughout the western United States, claiming over 1,000 completed projects. Annual revenue is approximately $26.1 million.

Industry: Bridge Construction & Civil Engineering
Address: North Highlands, California, United States
Employees: <25
Founded: 1984

Attack summary

Severity: high — Confirmed data publication by ransomware operator; company handles critical infrastructure projects (bridges, highways) and likely maintains sensitive project data, client contracts, and employee PII. Operational disruption to bridge construction could impact critical infrastructure.

BlackLock claims to have compromised MCM Construction's systems and exfiltrated data. The group has published the victim on their leak site, indicating data exfiltration rather than encryption-only disruption.

high

Data the group says was taken

AI dossier — extracted from the leak post

Employee records
Project documentation
Financial records
Client information
Operational data

What the group claims

Commercial & Residential Construction California, United States <25 Employees MCM Construction is a leading bridge construction company in the USA, known for building over 1000 critical structures across the West. Revenue $26.1 Million

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 blacklock

Based on the limited publicly available information, Blacklock is an emerging ransomware group first observed in May 2025, operating with apparent financial motivations targeting organizations across multiple countries and sectors. The group's origin and potential affiliations remain unclear from documented sources, and there is insufficient public reporting to determine whether they operate as a Ransomware-as-a-Service model or as an independent entity. With 64 documented victims since their emergence, Blacklock has demonstrated a broad targeting approach across the United States, Canada, Spain, India, and the United Kingdom, with particular focus on technology, construction, manufacturing, and consumer services sectors, though their attack methodology, initial access vectors, and encryption tactics have not been extensively documented by major security research organizations. Due to the group's recent emergence and limited public reporting from established threat intelligence sources, notable campaigns and specific technical details of their operations remain largely undocumented in publicly available security research. As of current reporting, the group appears to remain active given their recent emergence date, though comprehensive analysis of their operational status requires additional documentation from established cybersecurity authorities. The group has been linked to 64 public disclosures across our corpus. First observed on a leak site on May 16, 2025; most recent post July 2, 2025. The operation is currently inactive.

Timeline of this disclosure

May 30, 2025MCM Construction listed by blacklockon the group's public leak site

Records: 25 Employees
Ransom demanded: $26.1M

Other recent disclosures by blacklock

blacklock has been linked to 64 public victims on Darkfield. A sample of the most recent:

See the full blacklock dossier →

Sector and geography

This disclosure adds to ransomware activity in the Construction sector, which has 988 disclosures indexed across all operators we track. Geographically, MCM Construction is reported in United States, a country with 11,033 ransomware disclosures in our corpus.

If your organisation is affected

A listing by blacklock means MCM Construction 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 blacklock'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.