Organizations are becoming increasingly concerned about system availability as they experience more and more distributed denial-of-service (DDoS) attacks, a new study says.

The study, conducted by the Ponemon Institute and sponsored by Radware, surveyed 705 IT security professionals on issues related to downtime and DDoS.

While security pros have traditionally been focused on preventing data theft or corruption, today's professionals are more worried about system availability, the study says.

"DDoS attacks cost companies 3.5 million dollars every year," Ponemon says. "Sixty-five percent reported experiencing an average of three DDoS attacks in the past 12 months, with an average downtime of 54 minutes per attack.

"With the cost for each minute of downtime amounting to as much as USD 100,000 per minute - including lost traffic, diminished end-user productivity and lost revenues - it is no surprise that respondents ranked availability as their top cyber security priority," the study says.

Most organizations don't have the ability to strike back at attackers, according to Ponemon. "While 60 percent say they want technology that slows down or even halts an attacker's computer, the majority (63 percent) of respondents give their organizations an average or below average rating when it comes to their ability to launch counter measures," the report states. Three-quarters of organizations still rely on antivirus and anti-malware to protect themselves from attacks, Ponemon says.