Think your business is immune to the threat of ransomware? Think again.

Nearly 40 percent of enterprises were hit by ransomware in the past year, according to a new study sponsored by cyber-security firm Malwarebytes and conducted by Osterman Research. Moreover, 34 percent of those targeted lost money and 20 percent were forced to close up shop because of it.

Other alarming findings? US executives are "disproportionately targeted" and 96 percent of organizations aren't confident about their ability to stop this threat.

Osterman Research surveyed 540 CIOs, CISOs, and IT directors from companies with an average of 5,400 employees across the US, Canada, UK, and Germany. They found that nearly 80 percent of US companies have suffered a cyber attack in the last year, and more than half have experienced a ransomware incident.

"Over the last four years, ransomware has evolved into one of the biggest cyber-security threats in the wild, with instances of ransomware in exploit kits increasing 259 percent in the last five months alone," Malwarebytes Senior Security Researcher and ransomware expert Nathan Scott said in a statement.

The most prevalent ransomware attack vector? Email, the study found, with 46 percent of ransomware attacks originating via attachments or malicious links in messages.

As for the cost of attacks, the survey revealed that nearly 60 percent demanded more than $1,000 while 20 percent asked for around $10,000 and 1 percent tried to get companies to fork over more than $150,000. Globally, more than 40 percent of victims paid these ransom demands. Additionally, most spent more than an entire business day trying to shore up endpoints following an attack.

Even more concerning, though: "3.5 percent even said lives were at stake because of ransomware's debilitating effects," Malwarebytes reported.

The survey also suggests that healthcare and financial services organizations should be most concerned about ransomware. Both industries were targeted "well above" the average ransomware penetration rate of 39 percent—something we've seen at Hollywood Presbyterian Medical Center and Methodist Hospital in Henderson, Kentucky, among others.

Still, "any business in any region is incredibly vulnerable to ransomware," Malwarebytes CEO Marcin Kleczynski said in a statement. "Cybercriminals are increasing their use of ransomware in their attack strategies globally, causing business disruption, loss of files and wasted IT man-hours. In order to stay safe, businesses must invest heavily in both employee education and technology."

For more, check out How to Protect and Recover Your Business from Ransomware.