Disclosure context

About Medusa

Medusa, also known as MedusaLocker, is a financially motivated ransomware group that emerged in November 2022 and has since compromised 568 known victims across multiple countries. The group's origin and specific affiliations remain unclear from publicly available intelligence, though their operational patterns suggest they function as an independent ransomware operation rather than a documented Ransomware-as-a-Service model. Medusa primarily targets organizations in the United States, United Kingdom, Canada, Italy, and Australia, with a focus on business services, healthcare, manufacturing, and technology sectors, employing typical ransomware tactics including data encryption and likely exfiltration for double extortion purposes, though specific technical methodologies and initial access vectors have not been extensively documented in public threat intelligence reports. While the group has maintained a relatively high victim count since its emergence, detailed information about specific notable campaigns, high-profile victims, or major ransom demands has not been widely reported by major cybersecurity firms or law enforcement agencies. As of current intelligence assessments, Medusa appears to remain active in the threat landscape, continuing to target organizations across their established geographic and sectoral preferences. The group has been linked to 568 public disclosures across our corpus. First observed on a leak site on November 15, 2022; most recent post February 14, 2026. The operation is currently active.

Also tracked as: MedusaLocker.

Timeline of this disclosure

November 30, 2025Universidade Municipal de São Caetano listed by Medusaon the group's public leak site

Records: 1.000 Employees

Sector and geography

This disclosure adds to ransomware activity in the Education sector, which has 694 disclosures indexed across all operators we track. Geographically, Universidade Municipal de São Caetano is reported in Brazil, a country with 319 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

Universidade Municipal de São Caetano

Claimed by Medusa · listed 6 months ago

1.000 Employees

Records

Age

since listed · data leaked

Status timeline

Listed
Nov 30, 2025
Data leaked

At a glance

Group: Medusa
Status: Data leaked
Country: Brazil
Sector: Education
Listed on leak site: Nov 30, 2025
Records: 1.000 Employees

About the victim

AI dossier — public-source company profile

Universidade Municipal de São Caetano do Sul (USCS) is a public municipal university located in São Caetano do Sul, in the greater São Paulo metropolitan area, Brazil. It offers undergraduate and postgraduate programs across multiple fields and is administered by the municipality of São Caetano do Sul. As a public institution it serves thousands of students and staff.

Industry: Higher Education (Municipal University)
Address: São Caetano do Sul, São Paulo, Brazil

Attack summary

Severity: high — The disclosure status is 'data_published', confirming exfiltration and public release of data from a public university likely containing PII of students and staff at scale, which constitutes significant sensitive data exposure even absent confirmed regulated medical or financial records.

The Medusa ransomware group claims to have attacked Universidade Municipal de São Caetano do Sul and has published data, indicating exfiltration of institutional data; the specific data types and volume are not determinable from the truncated leak post.

high

Data the group says was taken

AI dossier — extracted from the leak post

Student records
Staff/faculty personal data
Administrative documents
Academic records

What the group claims

USCS offers a diverse range of educational programs including in-person and distance learning undergraduate degrees, technical courses, and postgraduate studies such as MBAs and doctorates. The university also provides non-degree courses aimed at skill enhancement and is equipped with facilities for secondary education. Services include free legal assistance, fiscal education, and health services, catering to both students and the community. With a focus on quality and flexibility, USCS serves a wide array of clients including students at various academic levels and professionals seeking further education. company is headquartered in Rua Santo Antônio, 50 – Centro, São Caetano do Sul, SP, CEP 09521-160. 501-1,000 Employees,

The leak post

captured from the group's site

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Sources

Leak posthttp://xfv4jzckytb4g3ckwemcny3ihv4i5p4lqzdpi624cxisu35my5fwi5qd.onion/detail?id=a4f6f6bd335ab7802859759b380d03f6

Source

Indexed 6 months 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.