Officials in Baltimore in the U.S. state of Maryland confirmed Wednesday that the city's 911 dispatch system was temporarily shut down because of a ransomware attack on the weekend.
No ransom request was made and no personal data was exposed, according to Baltimore Mayor's Office of Information Technology.
"The systems and the software and the files are all being investigated by the FBI (the U.S. Federal Bureau of Investigation) right now," chief information officer Frank Johnson said as quoted by local paper the Baltimore Sun.
The ransomware attacked the server of computer-aided dispatch system that would automatically respond to emergency calls, which led to the system's shutdown from Sunday to Monday.
Manual dispatching was activated during the nearly-22-hour malfunction.
According to Johnson, vulnerability was left after information technicians accidentally changed the system server's firewall when correcting a communication problem.
A ransomware attack also happened in the city of Atlanta last Thursday. Hackers paralyzed the city's online payment system and asked for a ransom of 51,000 U.S. dollars in bitcoin payment.