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Cyber Threat
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Ransomware victim Education

Universidade Municipal de São Caetano

Listed by Medusa on · organisation based in Brazil

uscs.edu.br

Disclosed
Nov 30, 2025
Leak-site listing date
Threat group
Medusa
372 victims listed
Country
Brazil
#7 most targeted
Sector
Education

ThreatAI analysis

Compiled from this incident record and the threat intelligence profile for Medusa. Figures and technique mappings are quoted from the source data, not inferred.

About the Medusa group

Medusa is a ransomware-as-a-service operation active since June 2021 that has targeted over 300 victims across critical infrastructure sectors including healthcare, education, legal, and manufacturing using double-extortion, with attacks surging 42% between 2023 and 2024 and a formal CISA advisory issued in early 2025. Medusa has listed 517 victims since January 2023.

How Medusa is documented to operate

Valid Accounts T1078 Stealth Persistence

Adversaries may obtain and abuse credentials of existing accounts as a means of gaining Initial Access, Persistence, Privilege Escalation, or Defense Evasion. Compromised credentials may be used to bypass access controls placed on various resources on systems within the network and may even be used for persistent access to remote systems and externally available services, such as VPNs, Outlook Web Access, network devices, and remote desktop. Compromised credentials may also grant an adversary increased privilege to specific systems or access to restricted areas of the network.

Mitigations: Application Developer Guidance, User Training, Password Policies, User Account Management, Privileged Account Management, Multi-factor Authentication

MITRE ATT&CK reference
External Remote Services T1133 Persistence Initial Access

Adversaries may leverage external-facing remote services to initially access and/or persist within a network. Remote services such as VPNs, Citrix, and other access mechanisms allow users to connect to internal enterprise network resources from external locations. There are often remote service gateways that manage connections and credential authentication for these services. Services such as Windows Remote Management and VNC can also be used externally. Access to Valid Accounts to use the service is often a requirement, which could be obtained through credential pharming or by obtaining the credentials from users after compromising the enterprise network.

Mitigations: Limit Access to Resource Over Network, Restrict Web-Based Content, Network Segmentation, Multi-factor Authentication, Disable or Remove Feature or Program

MITRE ATT&CK reference
Exploit Public-Facing Application T1190 Initial Access

Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network. The weakness in the system can be a software bug, a temporary glitch, or a misconfiguration. Exploited applications are often websites/web servers, but can also include databases (like SQL), standard services (like SMB or SSH), network device administration and management protocols (like SNMP and Smart Install), and any other system with Internet-accessible open sockets. On ESXi infrastructure, adversaries may exploit exposed OpenSLP services; they may alternatively exploit exposed VMware vCenter servers.

Mitigations: Vulnerability Scanning, Limit Access to Resource Over Network, Filter Network Traffic, Network Segmentation, Privileged Account Management, Application Isolation and Sandboxing

MITRE ATT&CK reference
Phishing T1566 Initial Access

Adversaries may send phishing messages to gain access to victim systems. All forms of phishing are electronically delivered social engineering. Phishing can be targeted, known as spearphishing. In spearphishing, a specific individual, company, or industry will be targeted by the adversary. More generally, adversaries can conduct non-targeted phishing, such as in mass malware spam campaigns. Adversaries may send victims emails containing malicious attachments or links, typically to execute malicious code on victim systems. Phishing may also be conducted via third-party services, like social media platforms.

Mitigations: Network Intrusion Prevention, Restrict Web-Based Content, User Training, Antivirus/Antimalware, Software Configuration, Audit

MITRE ATT&CK reference
Windows Management Instrumentation T1047 Execution

Adversaries may abuse Windows Management Instrumentation (WMI) to execute malicious commands and payloads. WMI is designed for programmers and is the infrastructure for management data and operations on Windows systems. WMI is an administration feature that provides a uniform environment to access Windows system components. The WMI service enables both local and remote access, though the latter is facilitated by Remote Services such as Distributed Component Object Model and Windows Remote Management. Remote WMI over DCOM operates using port 135, whereas WMI over WinRM operates over port 5985 when using HTTP and 5986 for HTTPS.

Mitigations: Execution Prevention, Behavior Prevention on Endpoint, User Account Management, Privileged Account Management

MITRE ATT&CK reference
Command and Scripting Interpreter T1059 Execution

Adversaries may abuse command and script interpreters to execute commands, scripts, or binaries. These interfaces and languages provide ways of interacting with computer systems and are a common feature across many different platforms. Most systems come with some built-in command-line interface and scripting capabilities, for example, macOS and Linux distributions include some flavor of Unix Shell while Windows installations include the Windows Command Shell and PowerShell. There are also cross-platform interpreters such as Python, as well as those commonly associated with client applications such as JavaScript and Visual Basic.

Mitigations: Restrict Web-Based Content, Limit Software Installation, Execution Prevention, Code Signing, Behavior Prevention on Endpoint, Privileged Account Management

MITRE ATT&CK reference

MITRE ATT&CK techniques attributed to Medusa across its recorded activity, not a finding about how Universidade Municipal de São Caetano was reached.

Vulnerabilities Medusa is recorded exploiting

2 of these 2 are in the CISA Known Exploited Vulnerabilities catalog, 2 of them recorded by CISA as used in ransomware campaigns. CVEs attributed to Medusa across its reported activity. There is no indication that any of these was involved in the Universidade Municipal de São Caetano incident — the source data does not record an entry point.

Incident analysis

Universidade Municipal de São Caetano was listed by Medusa ransomware, a group with 372 victims recorded in this database. The listing appeared on the group's leak site on November 30, 2025.

Universidade Municipal de São Caetano is based in Brazil and operates in the Education sector. Brazil ranks #7 worldwide for ransomware disclosures, with 532 victims in this database.

Sector context. Educational institutions often have under-resourced IT security teams and hold large amounts of student and faculty personal data, making them attractive targets for ransomware groups.

Medusa typically follows a double extortion model: data is exfiltrated from the victim's systems before files are encrypted, so the victim faces two demands at once — pay to restore access, and pay to keep stolen data unpublished. The leak site, where this listing appeared, is the lever for the second demand.

Source. Public leak-site disclosures aggregated via the ransomware.live API. The disclosure date is when the listing was published, which can differ from the date of compromise. This site does not publish or link to stolen data. Last updated .

Frequently asked questions

Was Universidade Municipal de São Caetano attacked by ransomware?

Yes. Universidade Municipal de São Caetano was listed as a victim of the Medusa ransomware group on November 30, 2025. The organisation is based in Brazil and operates in the Education sector. The disclosure appeared on the group's dark web leak site.

Which ransomware group attacked Universidade Municipal de São Caetano?

Universidade Municipal de São Caetano was attacked by Medusa ransomware. Medusa is one of the most active ransomware groups, having claimed 372 victims globally. The group typically employs a double-extortion model: encrypting the victim's files and threatening to publish stolen data.

When did the Universidade Municipal de São Caetano ransomware attack occur?

The ransomware attack on Universidade Municipal de São Caetano was disclosed on November 30, 2025. This date reflects when the victim was published on the threat group's leak site, which may differ from the actual date of initial compromise.

What data was stolen in the Universidade Municipal de São Caetano ransomware attack?

The specific data stolen from Universidade Municipal de São Caetano has not been independently verified by this platform. Ransomware groups typically exfiltrate data before encrypting systems and use the threat of publication to pressure victims. As a Education organisation, Universidade Municipal de São Caetano likely held student and faculty personal data and academic records.

How can organisations protect against Medusa attacks?

To defend against Medusa and similar threat actors, organisations should: maintain regular offline backups tested for restoration; implement network segmentation to limit lateral movement; deploy multi-factor authentication on all remote access; use endpoint detection and response (EDR) tools; conduct regular phishing and security awareness training; and monitor threat intelligence feeds for indicators of compromise (IOCs) associated with active groups.