Koka City in Shiga Prefecture, Japan, announced on November 12, 2026, that the server behind its municipal voice broadcast system was hit by a ransomware attack following unauthorized access, leaving both its voice broadcast receivers and outdoor loudspeakers unusable. Emergency alerts and other broadcasts have stopped, and the city is investigating whether the names or business names of people who have the receivers installed were leaked. As of the announcement, there was no timeline for recovery.

Voice Broadcast Receivers and Outdoor Loudspeakers Are Out of Service

According to Koka City's announcement, a malfunction in the voice broadcast system has made both the voice broadcast receivers and the outdoor loudspeakers unusable. The city says the cause was a ransomware attack on the system's server after it was accessed without authorization.

Ransomware is malicious software that encrypts data on servers and PCs so it can no longer be used, then demands money in exchange for restoring it. Some attackers also steal data first and threaten to publish it, so an attack can lead not only to system outages but also to data leaks.

The city says the following four types of broadcasts are currently suspended:

  • Emergency alerts
  • Paging broadcasts
  • "Okuyami" (obituary) notices provided by Aicom Koka
  • "Melody" broadcasts from the outdoor loudspeakers

The city's announcement does not say when the attack occurred or when it was discovered. It also has not disclosed how the attackers got in or how far the encryption of data extends. Aicom Koka, which provides the obituary notices, has posted a notice on its website under the same title, "Unauthorized Access to the Regional Information Infrastructure Facility (Voice Broadcast System)."

Names and Business Names of Receiver Installers May Have Leaked

The city is investigating the possibility that the names or business names of people who have voice broadcast receivers installed were leaked. It is not yet known whether any data was actually leaked or how many records may be involved, and the city says it will provide updates as soon as it learns more.

The only information the announcement identifies as possibly leaked is names and business names. It does not mention addresses, phone numbers, or any other information.

Emergency Alerts Will Go Out via LINE, Email, TV, and Radio

While voice broadcasts are unavailable, the city says it will deliver emergency alerts through the following channels:

  • Koka City's official LINE account
  • Aikoka Emergency Mail
  • Television
  • Radio
  • The Shiga Prefecture disaster-prevention app

The city says it will issue further notices once it learns more, including whether any data was leaked and when service may be restored. ITmedia NEWS also reported on the incident on November 13.

Residents Will Need Other Channels Until Service Is Restored

Voice broadcast receivers and outdoor loudspeakers let people hear announcements even when they are not looking at a smartphone screen. Residents who have relied on these broadcasts for emergency alerts will need to check information through the channels the city listed, such as its official LINE account, email, TV, radio, and the Shiga Prefecture disaster-prevention app, until the system is restored.

Paging broadcasts, obituary notices, and the melody broadcasts from outdoor loudspeakers have also stopped. Broadcasts that residents were used to hearing in daily life, not just in emergencies, will remain silent until the system comes back.

Our Take

Systems that deliver information to residents, such as disaster-prevention radio, rarely get much attention, but in a disaster they can be a matter of life and death. The cause of this incident and the system's configuration have not yet been disclosed, and we will be watching future announcements to see what countermeasures are taken.

The fact that the city is directing residents to alternative channels such as LINE, email, TV, radio, and the prefecture's disaster-prevention app shows the importance of having multiple ways to reach people. For other municipalities as well, letting residents know in advance what backup channels exist if voice broadcasts go down is likely to become more important.

Names and business names alone are unlikely to cause direct harm. However, the possibility that they could be misused in scams, such as phone calls or emails pretending to be from the city or related parties and asking for other personal information or money, cannot be ruled out. Residents should be cautious about any contact other than official notices from the city. How much the city ultimately discloses about the cause and countermeasures, including the entry point and whether backups existed, is also worth watching.

Summary

Koka City's voice broadcast system was hit by a ransomware attack, leaving its voice broadcast receivers and outdoor loudspeakers unusable. The names or business names of receiver installers may have been leaked, and while the city is investigating, there is no timeline for recovery. Until service is restored, emergency alerts will be delivered through the city's official LINE account, email, TV, radio, and the Shiga Prefecture disaster-prevention app.