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Cyber Threat
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Ransomware victim Government & Defense

Prefeitura Municipal de Arcos

Listed by Emperador on · organisation based in Brazil

arcos.mg.gov.br

Disclosed
Aug 18, 2026
Leak-site listing date
Threat group
Emperador
70 victims listed
Country
Brazil
#7 most targeted
Sector
Government & Defense

ThreatAI analysis

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

Emperador listed Prefeitura Municipal de Arcos on its dark web leak site on 18 August 2026; the government organization based in Brazil operates in the Government & Defense sector.

About the Emperador group

Emperador has listed 38 victims since August 2026.

Vulnerabilities Emperador is recorded exploiting

5 of these 5 are in the CISA Known Exploited Vulnerabilities catalog, 5 of them recorded by CISA as used in ransomware campaigns. CVEs attributed to Emperador across its reported activity. There is no indication that any of these was involved in the Prefeitura Municipal de Arcos incident — the source data does not record an entry point.

Incident analysis

Prefeitura Municipal de Arcos was listed by Emperador ransomware, a group with 70 victims recorded in this database. The listing appeared on the group's leak site on August 18, 2026.

Prefeitura Municipal de Arcos is based in Brazil and operates in the Government & Defense sector. Brazil ranks #7 worldwide for ransomware disclosures, with 532 victims in this database.

Sector context. Organisations in this sector hold valuable data and operational systems that ransomware groups seek to exploit for financial gain through encryption and data exfiltration.

Emperador 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files are encrypted, so the victim faces two demands at once — pay to restore access, and pay to keep stolen data unpublished.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 Prefeitura Municipal de Arcos attacked by ransomware?

Yes. Prefeitura Municipal de Arcos was listed as a victim of the Emperador ransomware group on August 18, 2026. The organisation is based in Brazil and operates in the Government & Defense sector. The disclosure appeared on the group's dark web leak site.

Which ransomware group attacked Prefeitura Municipal de Arcos?

Prefeitura Municipal de Arcos was attacked by Emperador ransomware. Emperador is one of the most active ransomware groups, having claimed 70 victims globally. The group typically employs a double-extortion model: encrypting the victim's files and threatening to publish stolen data.

When did the Prefeitura Municipal de Arcos ransomware attack occur?

The ransomware attack on Prefeitura Municipal de Arcos was disclosed on August 18, 2026. 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 Prefeitura Municipal de Arcos ransomware attack?

The specific data stolen from Prefeitura Municipal de Arcos 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 Government & Defense organisation, Prefeitura Municipal de Arcos likely held sensitive business data, client information, and operational records.

How can organisations protect against Emperador attacks?

To defend against Emperador 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.