NEW YORK (AP) — Dozens of countries were hit with a huge cyberextortion attack Friday 
that locked up computers and held users’ files for ransom at a multitude of hospitals,
 companies and government agencies.
It was believed to the biggest attack of its kind ever recorded.
The malicious software behind the onslaught appeared to exploit a vulnerability in 
Microsoft Windows that was supposedly identified by the National Security Agency
 for its own intelligence-gathering purposes and was later leaked to the internet.
Britain’s national health service fell victim, its hospitals forced to close wards and
 emergency rooms and turn away patients. Russia appeared to be the hardest hit, 
according to security experts, with the country’s Interior Ministry confirming it was
All told, several cybersecurity firms said they had identified the malicious software 
responsible for tens of thousands of attacks in more than 60 countries, including the 
United States, though its effects in the U.S. did not appear to be widespread, at least
 in the initial hours.
Computers were infected with what is known as “ransomware” — software that freezes 
up a machine and flashes a message demanding payment to release the user’s data. In 
the U.S., FedEx reported that its Windows computers were “experiencing interference”
 from malware, but wouldn’t say if it had been hit by ransomware.
Mikko Hypponen, chief research officer at the Helsinki-based cybersecurity company
 F-Secure, called the attack “the biggest ransomware outbreak in history.”
Security experts said the attack appeared to be caused by a self-replicating piece of 
software that enters companies and organizations when employees click on email
 attachments, then spreads quickly internally from computer to computer when 
employees share documents and other files.
Its ransom demands start at $300 and increase after two hours to $400, $500 and 
then $600, said Kurt Baumgartner, a security researcher at Kaspersky Lab. Affected
 users can restore their files from backups, if they have them, or pay the ransom;
otherwise they risk losing their data entirely.
Chris Wysopal of the software security firm Veracode said criminal organizations
 were probably behind the attack, given how quickly the malware spread.
“For so many organizations in the same day to be hit, this is unprecedented,” he said.
The security holes it exploits were disclosed several weeks ago by TheShadowBrokers, 
a mysterious group that has published what it says are hacking tools used by the NSA 
as part of its intelligence-gathering.
Shortly after that disclosure, Microsoft announced that it had already issued software 
“patches” for those holes. But many companies and individuals haven’t installed the
 fixes yet or are using older versions of Windows that Microsoft no longer supports 
and didn’t fix.
By Kaspersky Lab’s count, the malware struck at least 74 countries. In addition to 
Russia, the biggest targets appeared to be Ukraine and India, nations where it is 
common to find older, unpatched versions of Windows in use, according to the security
Hospitals across Britain found themselves without access to their computers or phone
 systems. Many canceled all routine procedures and asked patients not to come to the 
hospital unless it was an emergency. Doctors’ practices and pharmacies reported
 similar problems.
Patrick Ward, a 47-year-old sales director, said his heart operation, scheduled for Friday,
 was canceled at St. Bartholomew’s Hospital in London.
Tom Griffiths, who was at the hospital for chemotherapy, said several cancer patients 
had to be sent home because their records or bloodwork couldn’t be accessed.
“Both staff and patients were frankly pretty appalled that somebody, whoever they are, 
for commercial gain or otherwise, would attack a health care organization,” he said. 
“It’s stressful enough for someone going through recovery or treatment for cancer.”
British Prime Minister Theresa May said there was no evidence patient data had been 
compromised and added that the attack had not specifically targeted the National 
Health Service.
“It’s an international attack and a number of countries and organizations have been
 affected,” she said.
Spain, meanwhile, took steps to protect critical infrastructure in response to the attack.
 Authorities said they were communicating with more than 100 energy, transportation, telecommunications and financial services providers about the attack.
Spain’s Telefonica, a global broadband and telecommunications company, was among 
the companies hit.
Ransomware attacks are on the rise around the world. In 2016, Hollywood Presbyterian
 Medical Center in California said it had paid a $17,000 ransom to regain control of its 
computers from hackers.
Krishna Chinthapalli, a doctor at Britain’s National Hospital for Neurology & 
Neurosurgery who wrote a paper on cybersecurity for the British Medical Journal,
 warned that British hospitals’ old operating systems and confidential patient 
information made them an ideal target for blackmailers.
He said many NHS hospitals in Britain use Windows XP software, introduced in 
2001, and as government funding for the health service has been squeezed, “IT budgets 
are often one of the first ones to be reduced.”
“Looking at the trends, it was going to happen,” he said. “I did not expect an attack on
this scale. That was a shock.
Lawless reported from London. Parra reported from Madrid.