Suisun City’s city council declared a state of emergency on Saturday after a Friday cyberattack compromised information technology systems, forcing the city to shut down its entire network and reroute emergency dispatch operations.
Malicious software infected and compromised city IT systems at approximately 5:45 a.m. Friday, according to city officials. The attack affected critical public safety operations, including 911 routing, police and fire dispatch, records and other city services.
To contain the attack and preserve evidence for a federal investigation, the city shut down its entire IT network, officials said. The city also activated its Emergency Operations Center and is working with federal, state and regional agencies, including the FBI, Department of Homeland Security and California Office of Emergency Services.
Despite the disruption, officials said there is no imminent threat to the public and emergency services remain operational.
Suisun City dispatchers are taking calls through the Solano County dispatch center, while Suisun City police officers and firefighters continue responding to calls for service. Online city services and internal operations remain temporarily unavailable as cybersecurity experts work to investigate the incident and restore systems.
The city council held a special meeting at 11 a.m. Saturday, declaring a state of emergency under Government Code 8630. The declaration allows the city to quickly access emergency support services and seek reimbursement for costs associated with the cybersecurity incident.
The city first notified residents of the attack Friday night, saying the incident had affected services at City Hall and public safety departments. Officials said at the time that many online systems and internal operations were unavailable and promised an update within 24 hours.
The attack appears to be the first known incident in Solano County in which a cyberattack directly compromised local public safety IT infrastructure and forced emergency dispatch operations to be rerouted. While municipalities elsewhere in the Bay Area and across the country have experienced attacks targeting emergency infrastructure, local public safety systems in Solano County had not previously experienced a disruption of this nature.
For example, Foster City declared a state of emergency after a severe ransomware attack in March paralyzed nearly all of the city’s internal government operations. The attack knocked both emergency and non-emergency phone lines for the Foster City Police Department offline. Nearby cities provided mutual aid for physical police responses while officials worked to bypass and restore the city’s disrupted digital dispatch system.
The Suisun City incident is not, however, the first major cyberattack to affect a Solano County organization.
In April 2024, hackers disrupted the IT network used by Solano County libraries, taking public internet and computer services offline for nearly four months. The attackers reportedly demanded a $100,000 ransom and threatened to release sensitive data. Full connectivity was restored in late July 2024.
NorthBay Health, which operates VacaValley Hospital in Vacaville and the NorthBay Medical Center in Fairfield, also experienced a significant network intrusion in April 2024. The health system was forced to use emergency offline procedures while responding to the attack. A subsequent forensic investigation found that an unauthorized third party had taken internal files containing sensitive personal and medical information. The breach was ultimately determined to have affected approximately 569,000 individuals, with identity protection and credit monitoring notifications issued in 2025.
The nature of the Suisun City attack, including whether data was stolen or whether a ransom was demanded, has not been disclosed. The incident remains under investigation.
The city said it will continue providing updates through its cybersecurity information page at Suisun.com/CybersecurityUpdates.