FOX NEWS - Another widespread cyber attack is causing massive disruptions around the world Tuesday.
Pharmaceutical giant Merck (MRK) became the first major U.S. company impacted by the ransomware, annoucing mid-day Tuesday its "computer network was compromised" as part of the global hack.
Ukraine has been hit particularly hard as government and company officials have reported serious intrusions across the Ukrainian power grid, banks and government offices. The country's prime minister says that the cyber attack affecting his country is "unprecedented," but "vital systems haven't been affected."
Russia's top oil producer Rosneft has said it has been hacked, as well as Danish shipping giant A.P. Moller-Maersk and Britain's WPP--the largest advertising company in the world.
Ukrainian Deputy Prime Minister Pavlo Rozenko on Tuesday posted a picture of a darkened computer screen to Twitter, saying that the computer system at the government's headquarters has been shut down.
There's little concrete information about who might be behind the disruption, but technology experts said it bears the hallmarks of ransomware, the name given to programs that hold data hostage by scrambling it until a payment is made.
"[These type of attacks are] absolutely becoming more common," SonicWall president Bill Conner told FOX Business Tuesday. "This is a threat vector that is increasing dramatically and creating a lot of havoc."
Security experts say Tuesday's cyberattack shares something in common with last month's WannaCry attack: Both spread by using digital break-in tools purportedly created by the U.S. National Security Agency and recently leaked to the web.
Conner also compared the Petya malware -- what is spreading now -- to WannaCry in the sense that it is a reinvented version of itself and mutations can happen in real-time.
"These new threats have increased … someone can create some of these for disruption and other people can [initiate] them for money," he said.
It's not clear whether or why the ransomware has suddenly become so much more potent, but Bitdefender analyst Bogdan Botezatu said that it was likely spreading automatically across a network, without the need for human interaction. Self-spreading software, often described as "worms," are particularly feared because they can spread rapidly, like a contagious disease.
"It's like somebody sneezing into a train full of people," said Botezatu. "You just have to exist there and you're vulnerable."
Conner said it is important every business have a plan in place in the event of a cyber-attack because the onset of these type of attacks are just beginning.
The world is still recovering from a previous outbreak in May of ransomware, called WannaCry or WannaCrypt, which spread rapidly across the world using digital break-in tools originally created by the U.S. National Security Agency and recently leaked to the web. That cyber attack impacted everything from major international companies to hospitals.
This particular variant of ransomware leaves a message with a contact email; several messages sent to the address were not immediately returned.