Was Colegio María Inmaculada (CMI) hit by ransomware?

Colegio María Inmaculada (CMI) was listed by the medusalocker ransomware operation (Costa Rica), 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 medusalocker ransomware group?

medusalocker 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 Colegio María Inmaculada (CMI) breach?

medusalocker published data attributed to Colegio María Inmaculada (CMI). Darkfield captured the leak post and a screenshot of the listing.

Ransomware victim disclosure

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Colegio María Inmaculada

listed as Colegio María Inmaculada (CMI) · Claimed by Medusalocker · listed 1 month ago

40d

Age

since listed · data leaked

Status timeline

ListedMay 5, 2026
Data leakeddate unknown

At a glance

Group: Medusalocker
Status: Data leaked
Country: Costa Rica
Sector: Education
Listed on leak site: May 5, 2026

About the victim

AI dossier — public-source company profile

Colegio María Inmaculada (CMI) is a Catholic educational institution located in Moravia, Costa Rica. The school operates standard IT infrastructure including domain controllers and web servers to support institutional operations.

Industry: Education – Catholic Secondary School
Address: Moravia, Costa Rica

Attack summary

Severity: medium — Educational institution with confirmed network compromise and server access; no proof files or specific data inventory disclosed; no ransom demand stated. Risk to student/staff PII is material but unconfirmed.

MedusaLocker claims to have compromised the school's network, accessing internal servers (CMI-DC01, CMI-APP, CMI-HTTP2, main-server1/2) and local domain (cmi.local). The group's post indicates system access but provides no specific details on data exfiltration or encryption.

medium

Data the group says was taken

AI dossier — extracted from the leak post

internal network infrastructure
domain controller data
application servers

What the group claims

Catholic school in Moravia, Costa Rica. Domain cmi.local / mariainmaculada.ed.cr. Servers: CMI-DC01, CMI-APP, CMI-HTTP2, main-server1/2.

Sources

Victim sitemariainmaculada.ed.cr
Leak posthttp://t33zoj4qwv455fog7qnb2azi5xcdxkixughmmduzbw2rtdgryqfbh6id.onion/company/baratai/

Source

Indexed 1 month 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 medusalocker

MedusaLocker is a ransomware operation first publicly documented around 2019, though the activity cluster reflected in this dataset shows observed campaigns beginning in November 2022, driven primarily by financial motivation with no known ideological or hacktivist agenda. The group is believed to operate out of or with ties to Eastern Europe, functioning as a Ransomware-as-a-Service model that allows affiliates to deploy the ransomware in exchange for a share of ransom proceeds, a structure documented in a joint advisory published by CISA, FBI, FinCEN, and HHS in June 2022. MedusaLocker actors typically gain initial access through phishing emails, exploitation of vulnerable Remote Desktop Protocol configurations, and compromised network devices, subsequently deploying the ransomware payload which encrypts victim files using AES-256 combined with RSA-2048 encryption while also exfiltrating sensitive data prior to encryption to enable double extortion pressure. Based on available telemetry, the group has claimed at least 67 known victims, with targeting concentrated heavily in the United States, United Kingdom, Brazil, France, and Israel, spanning sectors including business services, manufacturing, technology, and education, consistent with the opportunistic rather than highly selective targeting pattern characteristic of RaaS affiliate programs. As of the time of writing, MedusaLocker remains an active threat with no confirmed law enforcement disruption, takedown operation, or confirmed rebrand publicly attributed to the group by major intelligence or law enforcement agencies. 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, 2026Colegio María Inmaculada (CMI) listed by medusalockeron the group's public leak site

Other recent disclosures by medusalocker

medusalocker has been linked to 67 public victims on Darkfield. A sample of the most recent:

See the full medusalocker dossier →

Sector and geography

This disclosure adds to ransomware activity in the Education sector, which has 1,082 disclosures indexed across all operators we track. Geographically, Colegio María Inmaculada (CMI) is reported in Costa Rica, a country with 2 ransomware disclosures in our corpus.

If your organisation is affected

A listing by medusalocker means Colegio María Inmaculada (CMI) 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.
Monitor for the data appearing on medusalocker'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.