A key component of malware wreaking havoc on American cities was created by the National Security Agency, The New York Times reports. The NSA first lost control of the malware, called EternalBlue, in 2017. Since then, EternalBlue has been used by cybercriminals around the world. The tool has now made its way back to its birthplace—Baltimore, Maryland. Cybercriminals have begun to target vulnerable city governments, such as Baltimore, which is located only a short drive from NSA headquarters where the malware was developed.

Along with several other cities across the country, Baltimore has been fighting a cyberattack by digital extortionists using EternalBlue. On May 7, attackers froze thousands of computers in the city, shut down email, disrupted real estate sales, water bills, health alerts and many other government services. The NSA and FBI still don't know whether the attackers, who call themselves the Shadow Brokers, are foreign agents or disgruntled employees. Baltimore officials have refused to pay a ransom of $100,000 in Bitcoin in order to free files, leaving the city in gridlock.