Macaé Municipality

Macaé Municipality, also referred to as Maca Municipality, is a local government entity headquartered in Brazil that provides administrative and public services to the residents of the city of Macaé. Its core responsibilities include municipal administration, tax collection and management, and the delivery of public health programmes such as COVID‑19 vaccination campaigns. As a municipal authority it operates within the Brazilian federal system, exercising regulatory authority over local taxation and community health initiatives while serving the geographic area of Macaé. The organisation maintains public‑facing services that remain accessible to citizens even during internal disruptions, reflecting its commitment to continuity of essential municipal functions.

On 3 June 2023 the municipality experienced a ransomware attack that targeted its internal network, with suspected entry points including USB drives or VPN connections. The malicious software compromised file servers, systems and databases, corrupting data and rendering most internal operations inoperable while public‑facing services continued to function without interruption. In response, the municipality isolated the affected equipment, launched a forensic analysis, and pursued legal action accompanied by a formal police cybercrime report. The attack resulted in unrecovered data from tax exemption protocols, prompting the organisation to directly contact impacted taxpayers to request re‑submission of the missing information. No dedicated leak site was associated with the incident, yet the municipality proceeded with IT modernization plans that included the implementation of enhanced security infrastructure. Despite the disruption, COVID‑19 vaccination operations were maintained, demonstrating the organisation’s ability to sustain critical public health efforts during a cybersecurity crisis.