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high severity June 05, 2023 · 3 min read Unverified claim — what this is

Concremat constructions Listed by medusa Ransomware Group

If you are a customer of Concremat constructions, here’s what is being claimed, and what it would mean for you.

Concremat constructions was listed on Medusa's leak site. Medusa claims to have stolen internal data. This is the group's claim, not a confirmed finding.

Concremat constructions Listed by medusa Ransomware Group

Concremat Companies, a Brazilian engineering and construction firm founded in 1972, was listed on the Medusa ransomware group's leak site on June 05, 2023. The listing indicates that internal files were exfiltrated during a ransomware attack on the Rio de Janeiro-headquartered company, which provides urban development studies, environmental management systems, and sustainable territorial planning services. Anyone whose personal or professional data touched Concremat's systems may now face heightened exposure.

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Primary Disclosure Details

The Medusa leak site listing states that Concremat suffered a ransomware incident in which internal files were exfiltrated. The disclosure does not quantify the number of affected records, specify which exact data types were taken beyond the generic description of internal files, or reveal any ransom demand. Public access to the leak site via mirrors such as ransomware.live shows the entry dated June 05, 2023, with a unique identifier linking it to the company's profile. No official breach notification from Concremat has surfaced in regulator filings or direct customer communications at the time of analysis.

Why This Matters for You and Your Family

When a company that handles urban planning, environmental studies, or government contracts is breached, the ripple effects reach ordinary people. Your name, address, national identification number, contact details, or employment records may have been stored in the very internal files now held by attackers. For families in Brazil or those who have worked with infrastructure projects, this can translate into concrete risks: unexpected phishing emails, fraudulent loan applications, or targeted scams that reference real project details only an insider would know. Even if you never directly contracted with Concremat, subcontractors, suppliers, or local government partners often share household information that ends up in the same systems.

Doxxing and Identity-Chain Implications

Exfiltrated internal files frequently contain spreadsheets, emails, and project documents that link personal identifiers to workplace accounts, vendor lists, and correspondence. Attackers can chain these fragments with data from previous breaches to build a complete profile: email addresses become gateways to linked social-media handles, phone numbers tie to family members, and project metadata can reveal home addresses tied to development sites. Once such chains exist, credential leaks like this one routinely cascade into gaming-account takeovers, especially for children whose parent accounts reuse corporate passwords or share devices. The result is not a single leak but an expanding map of your digital life that criminals can exploit for identity theft, harassment, or further extortion.

Medusa Group's Known Track Record

Public reporting attributes the Medusa ransomware group with emerging in mid-2021. The gang has targeted organizations across North America, Europe, and Latin America, with notable prior victims including manufacturing firms, healthcare providers, and municipal governments. Their typical playbook begins with initial access gained through compromised remote desktop credentials or phishing, followed by rapid exfiltration of sensitive files before encryption. Medusa then operates a double-extortion model: they threaten to publish stolen data on their leak site if the victim refuses to pay, often providing sample documents as proof. The group maintains an active onion-site presence and updates listings on a near-weekly basis, indicating a structured and persistent operation.

What to do

  • Run a DoxxScan to map every link between your handles, emails, phone numbers, and real identity, including any ties to Concremat or its partners.
  • Rotate any password you ever used at Concremat or related engineering platforms anywhere it has been reused, and immediately enable 2FA through an authenticator app rather than SMS.
  • Enable continuous DoxxScan monitoring across 13.1B+ breach records and 100+ platforms so the next exposure surfaces in hours instead of months.
  • Cover the household with DoxxScan family protection that extends to dependents and children's gaming accounts vulnerable to credential chaining from this claimed breach.
  • Let remediation specialists handle data-broker takedown requests and opt-out processes that arise from the identity chains created by the leaked internal files.

The Medusa listing of Concremat on June 05, 2023, is a reminder that infrastructure and engineering firms hold data that directly shapes everyday lives and identities. Acting quickly on credential hygiene and identity mapping can limit the damage before criminals stitch together the next link in the chain. DoxxScan by GalaxyWarden delivers continuous monitoring across 13.1B+ breach records and 100+ platforms, AI-powered identity-chain mapping, hands-on remediation by specialists, and full household coverage that includes children's gaming accounts.

What the free scan actually returns

Sample resultyou@email.comIllustrative — not a real person

Found on people-search siteswe remove these

These listings are live, public, and legal to remove — and removing them is what we do.

value redacted in this sampleage, relatives, address historySpokeo
value redacted in this samplephone, household, property recordsBeenVerified
value redacted in this sample582 companies checked

Found in breach recordsverifiedreported — unverified

Each record is labeled: confirmed breach data, or an attacker’s claim no one has verified.

verifiedvalue redacted in this samplepassword + phone · 2024telecom breach
unverifiedvalue redacted in this sampleclaimed in ransomware listing · 2026leak-site claim

Leaked data cannot be deleted from the internet — anyone claiming otherwise is lying. Broker listings can be removed. We do the second, and show you exactly what to fix from the first.

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Report details & sourcing

Severity High the filing does not enumerate what was exposed
Disclosed June 05, 2023
Last reviewed August 8, 2026
Affected Unconfirmed
Unverified claim — what this report is
This page documents a public listing on a ransomware/extortion group’s leak site, tracked via public threat-intelligence sources. A listing is the attacker’s claim. GalaxyWarden aggregates and reports such claims; we have not independently verified that a breach occurred, what data (if any) was taken, or the accuracy of anything the group asserts, and the named organisation has not necessarily confirmed the incident. Sections above describe what the listing shows and the group’s documented history — not verified findings about the named organisation. If you represent this organisation and believe anything here is inaccurate, tell us and we’ll review it promptly.
Editorial & sourcing policy
GalaxyWarden is a breach-monitoring service and news aggregator. We do not exfiltrate, host, purchase, or redistribute stolen data. Breach information is compiled from publicly accessible sources and threat-intelligence platforms, and is reported as claims attributed to their source. We promptly correct or remove material shown to be inaccurate — see our content & takedown policy or write to support@galaxywarden.com.
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