Incident BriefingsSuisun City malware incident and network shutdown

Suisun City malware incident and network shutdown

Malware compromised city IT. A network shutdown disrupted services while dispatchers continued taking emergency calls through Solano County.

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Summary

  • Environment: Municipal IT, dispatch and city-service systems
  • Operational impact: Network shutdown; payments and permits affected
  • Financial impact: No quantified loss in the retained evidence
  • Record status: Developing record. Reviewed October 7, 2026; updated as evidence emerges.

What happened

Suisun City reported that malware compromised its IT systems at roughly 5:45 a.m. on August 7, 2026. Its official notice described a network-wide shutdown. [2]

Impact

  • City systems supporting 911 routing, dispatch and records were affected; dispatchers took calls through Solano County while police and fire continued responding. [2]
  • A city spokesperson told KQED that emergency calls continued while residents faced payment and permit disruption. [1]

Timeline

  1. Malware incident begins

    The city dated the compromise to Friday morning.

    [2]

  2. Emergency declared

    The council announcement followed a special meeting.

    [2]

  3. Briefing updated

    This briefing was last reviewed and updated on October 7, 2026.

Threat Group & Attack Vector

The city described malicious software. The retained record does not establish an initial access method, ransomware family or confirmed data exposure. [2]

Actors

  • No threat actor group has been identified in the retained evidence.

TTPs

  • No specific MITRE ATT&CK technique is currently mapped for this case.

Response

The shutdown aimed to contain the threat and preserve evidence. The city activated its Emergency Operations Center and coordinated with federal, state and regional agencies. [2]