Disclosure context

About medusalocker

MedusaLocker is a ransomware group that emerged in November 2022, operating with primarily financial motivations and targeting organizations across multiple sectors including technology, energy, healthcare, and manufacturing. The group's origin and specific affiliations remain largely undocumented in public threat intelligence reports, though their operational patterns suggest they may operate as part of the broader ransomware-as-a-service ecosystem that has proliferated in recent years. With 51 documented victims primarily concentrated in the United States, United Arab Emirates, Germany, Canada, and Antigua and Barbuda, MedusaLocker appears to focus on opportunistic targeting rather than specific geographic or sectoral specialization. The group's attack methodology and specific technical capabilities have not been extensively documented by major threat intelligence organizations, though their targeting of critical infrastructure sectors including healthcare and energy suggests they likely employ common ransomware tactics such as network encryption and potential data exfiltration. No major high-profile attacks or significant law enforcement disruptions against MedusaLocker have been publicly reported by CISA, FBI, or other major security agencies. The current operational status of MedusaLocker remains unclear due to limited public documentation, though the relatively recent emergence date suggests the group may still be active or have transitioned to other operations. The group has been linked to 67 public disclosures across our corpus. First observed on a leak site on November 15, 2022; most recent post May 5, 2026. The operation is currently active.

Timeline of this disclosure

May 5, 2026Atencio Engineering listed by medusalockeron the group's public leak site

Sector and geography

This disclosure adds to ransomware activity in the Construction sector, which has 415 disclosures indexed across all operators we track. Geographically, Atencio Engineering is reported in United States, a country with 7,392 ransomware disclosures in our corpus.

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.

Ransomware victim disclosure

← All victims

Atencio Engineering

Claimed by medusalocker · listed 15 days ago

15d

Age

since listed · data leaked

Status timeline

Listed
May 5, 2026
Data leaked

At a glance

Group: medusalocker
Status: Data leaked
Country: United States
Sector: Construction
Listed on leak site: May 5, 2026

About the victim

AI dossier — public-source company profile

Atencio Engineering is a civil engineering and land surveying firm operating in southern Colorado, serving clients in Las Animas County, Pueblo County, and the Florence, CO area. The firm provides services including site plans, boundary surveys, OWTS (septic system) design, fire line design, elevation certificates, and floodplain analysis. It appears to be a small regional practice focused on residential and commercial land development support.

Industry: Civil Engineering & Land Surveying
Address: Las Animas County / Pueblo County / Florence, CO area, United States

Attack summary

Severity: medium — Data has been published (disclosed status: data_published), indicating confirmed exfiltration of business and client project files. However, the data involves engineering and survey documents rather than large-scale regulated PII, medical, financial, or government data, limiting severity to medium.

MedusaLocker claims to have exfiltrated data from Atencio Engineering and has published the data. No ransom amount or specific data volume was stated in the post.

medium

Data the group says was taken

AI dossier — extracted from the leak post

Site plans
Boundary survey records
OWTS/septic design documents
Fire line design files
Elevation certificates
Floodplain analysis reports
Client records (Las Animas County, Pueblo County, Florence CO area)

What the group claims

Civil engineering & land surveying firm. Services: site plans, boundary surveys, OWTS (septic) design, fire line design, elevation certificates, flood plain analysis. Clients in Las Animas County, Pueblo County, Florence CO area.

The leak post

captured from the group's site

File Manager File Manager home page BARAAAI Data is being prepared for publication. BAPAMAI Data is being prepared for publication. BAUARAI Data is being prepared for publication. BAVADAI Data is being prepared for publication. BAVACAI Data is being prepared for publication. BAVAQAI Data is being prepared for publication. Raycolighting DEMO 3137 S Alameda Street, Los Angeles, CA 90058, USA $10 000 Organization with 2 emails extracted. Domain: raycolighting.com baralai Data is being prepared for publication. CEAGESP / Netfeirasp DEMO São Paulo, Brazil $20 000 Brazilian produce wholesale market network. Domain netfeirasp.ceagesp (CEAGESP). Also demarchibrasil.com.br accounts. Colegio María Inmaculada (CMI) DEMO Moravia, San José, Costa Rica $50000 Catholic school in Moravia, Costa Rica. Domain cmi.local / mariainmaculada.ed.cr. Servers: CMI-DC01, CMI-APP, CMI-HTTP2, main-server1/2. Académie de Montpellier / CSJM DEMO Béziers, Occitanie, France $15000 French public school network. Domain CSJM.BEZIERS, part of Académie de Montpellier (ac-montpellier.fr). Occitanie region (laregion.fr). Teacher and admin staff credentials. Palmers Relocations DEMO Victoria, Australia $63 000 Australian …

Sources

Leak posthttp://t33zoj4qwv455fog7qnb2azi5xcdxkixughmmduzbw2rtdgryqfbh6id.onion/company/atencio-engineering/

Source

Indexed 15 days 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.