Milwaukee County tornado sirens now encrypted to guard against hackers

Milwaukee County’s Office of Emergency Management this week installed new technology on its tornado warning sirens to better-guard them against potential hacks. 

Last year, a hack of the weather sirens in Dallas, Texas resulted in more than 150 of them blaring for 90 minutes in the early hours of the morning. 

Following the hack in Dallas, Milwaukee County determined its sirens were vulnerable to a similar type of tampering. 

To date, no one has attempted to hack the 57 sirens in Milwaukee County. 

But Monday, the county finished up the installation of encryption technology meant to keep the sirens protected against cybersecurity threats. 

Roughly half of the 57 sirens are owned by the county. The other half are owned by local municipalities. 

However, the county controls the activation of all the sirens from its 911 Center Downtown. It spent $47,000 to upgrade all of the sirens across Milwaukee County, including the ones owned by local governments. 

The signals sent from the 911 Center to the sirens across the area will now be encrypted. They were previously unencrypted. 

Erik Viel, Radio Services Director for the Office of Emergency Management, said it’s the same federal encryption standard used by the CIA and FBI. 

“There’s a key that scrambles all the information that’s sent over the airwaves,” Viel said. “Then an encryption card at each siren decrypts it and executes whatever command we sent over.” 

“If someone were to try and send signals to our sirens and they don’t have the specific encryption key, the sirens won’t acknowledge or respond to it,” Viel also said.

The company American Signal Corporation installs and maintains all of Milwaukee County’s sirens. 

Marketing Manager Jenny White said ASC developed the encryption communication card technology shortly after the hack in Dallas as a way to protect older-model sirens from tampering. 

“Of course, 20 or 30 years ago, not many people were using computers,” White said. “Things have changed over the decades.” 

"Hackers continue to get more and more sophisticated," White also said. 

Viel said emergency officials will be testing the new encryption technology over the next couple of weeks to make sure it’s working properly. 

That includes a test Wednesday afternoon. 

“I believe we’re just going to do growl testing, so it won’t be the real noisy activation,” Viel said. 

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