Large businesses are constantly targeted by hackers, andrecent reports suggest that many large companies don't take thenecessary precautions to prevent outsiders from accessing theircomputer systems.

But the threat of cyberattacks is even greater for health careorganizations, over 80 percent of which report being targeted by anattack in a recent survey by KPMG, a global professional servicesconsulting firm.

The survey polled 223 executives of for-profit and non-profithealth care organizations worth at least $500 million.

Forty-four percent of the executives said their organization hadbeen subjected to between one and 50 cyberattacks in the past 12 months.Another 38 percent said their company had experienced between 50and 350 attacks, while 13 percent said they were attacked more than350 times.

Most frightening for business and consumers alike, 25 percent ofrespondents said their organization either lacked the ability todetect cyberattacks in real time or that they didn't know whetherit could or not.

“They are probably compromised and don’t even know it,”said Michael Ebert, KPMG partner and health care leader for thefirm’s Cyber Practice.

Nevertheless, most executives are clearly aware of the dangerthat exists from cyberattacks. But not everybody agrees on wherethe likely attacks will come from. Asked to cite likely sources ofa breach, 65 percent said external attacks were a big concern,while 48 percent cited the sharing of data with third-parties.Thirty-five percent identified theft or breaches by employees and35 percent said wireless computers were a likely risk. Only 27percent said that substandard firewalls might be a likely issue.

UCLA Health System announced last month that it had beenthe victim of a cyberattack that may have compromised confidentialdata of as many as 4.5 million patients.

The survey also shed light on what executives fear the impact ofa cyberattack could be. The most common fear was the presence ofmalware that could infect a system, while 57 percent say they werevery concerned about the theft of patient data.

While KPMG noted that health care organizations were at a higherrisk of cyberattacks than most other businesses, they are nottargeted as often as financial institutions.