Playing prank on a city

By Balamurugan Selvaraj Published on Apr 18, 2017 02:44 PM IST

Have you ever fooled anyone with a life-threating prank? Often, many do this for fun. But can you imagine, what would happen if a city's emergency security system alerts the public of danger as a prank?

A few weeks back, an unknown hacker dialled 156 Dallas outdoor emergency sirens loud for nearly two-and-a-half hours and created chaos among the residents of Dallas.

It seems that in 2007, Federal Signal installed the Dallas outdoor emergency warning system powering 156 sirens in the city. The emergency sound alarm is used for warning residents during natural calamities such as tornado.

On 7 April, around 4,400 residents called 911 emergency service to enquire about the emergency alarm. Though the city officials tried their best to inform residents about the prank, the emergency alarm flooded people with panic.

Director of Dallas Office of Emergency Management (OEM), Rocky Vaz, said, "The alarms blasted about 15 times for 90-seconds. You can even watch video footage of the incident posted by some people on the social media. The OEM technicians were eventually able to shut down the warning system and are working to keep this from happening again by implementing more safety measures."

Many researchers suggested that some hackers may have hijacked the alarm system by exploiting an issue in the vulnerable computer network. But, actually, leaving the vulnerable system network as leisure, hackers were able to get their hands on it through radio signals.

On 10 April, Dallas city manager, T C Broadnax, clarified the issue. He said, "The hacker used a radio signal that spoofed the system used to control the siren network centrally. I don't want someone to understand how it was done so that they could try to do it again. It was not a system software issue; it was a radio issue."

As of now, there are no clear details about the emergency alert system (EAS) of the US. If provided, the chances to hacking the emergency sirens may literally increase. But the system works on 'tonal type system', which is controlled by the EAS broadcast over the National Weather Service's weather radio.

At present, Federal Communications Commission (FCC) uses 700MHz range frequency for public safety.

It has been heard that the hacker who initiated the alarm managed to gain access to the siren system documentation.

They had played with the command signal repeatedly to identify the exact tonal commands which initiated the alarm.

After this breach, the EAS was closed for many hours and activated after inducing some encryption methods to secure language of tones.

In Dallas' history, this is the second time a prank threat has been done. Last year, an unknown hacker took over the traffic signals of Dallas and had fun with it.

About this incident; Dallas Mayor Mike Rawlings, quoted on his Facebook page, "It is yet another serious example of the need for us to upgrade and better safeguard our city’s technology infrastructure."

This case has been notified to FCC for further investigation.