From The New York Times: 

HOUSTON — At the public library in Wilmer, Tex., books were checked out not with the beeps of bar code readers but with the scratches of pen on notebook paper. Out on the street, police officers were literally writing tickets — by hand. When the entire computer network that keeps the small town’s bureaucracy afloat was recently hacked, Wilmer was thrown into the digital Dark Ages.

“It’s weird,” said Jennifer Dominguez, a library assistant. “We’ve gone old school.”

This has been the summer of crippling ransomware attacks. Wilmer — a town of almost 5,000 people just south of Dallas — is one of 22 cities across Texas that are simultaneously being held hostage for millions of dollars after a sophisticated hacker, perhaps a group of them, infiltrated their computer systems and encrypted their data. The attack instigated a statewide disaster-style response that includes the National Guard and a widening F.B.I. inquiry.

More than 40 municipalities have been the victims of cyberattacks this year, from major cities such as Baltimore, Albany and Laredo, Tex., to smaller towns including Lake City, Fla. Lake City is one of the few cities to have paid a ransom demand — about $460,000 in Bitcoin, a cryptocurrency — because it thought reconstructing its systems would be even more costly.

In most ransomware cases, the identities and whereabouts of culprits are cloaked by clever digital diversions. Intelligence officials, using data collected by the National Security Agency and others in an effort to identify the sources of the hacking, say many have come from Eastern Europe, Iran and, in some cases, the United States. The majority have targeted small-town America, figuring that sleepy, cash-strapped local governments are the least likely to have updated their cyberdefenses or backed up their data