Hundreds of US municipalities, schools and health organizations have been hit by ransomware in 2019, leading to massive service disruptions, a new study showed. Researchers at the security firm Emsisoft said at least 621 government entities, healthcare providers and school districts, colleges and universities were affected by ransomware in the last nine months. The attacks which lock up computer networks if a ransom is not paid has led to disruption of municipal and medical services and the closing of some schools. The study found that hackers seek vulnerabilities in older computer networks. The researchers said the use of cyber insurance may be making ransomware more profitable than it otherwise would be and incentivizes further attacks. A report earlier this year by the Internet Society found global losses from ransomware rose by 60 percent last year to $8 billion. Emsisoft said at least 68 state, county and municipal entities were hit by ransomware including widely publicized incidents in many US states where a $5.3 million demand was issued. The report found 62 incidents involved 1,051 school districts and other educational establishments, along with 491 attacks targeted hospitals and healthcare facilities.