Social-networking sites could give hackers a backdoor into corporate IT platforms and databases, putting businesses at risk for malicious cyber attacks as more adults access these sites from computers at work., according to a study released Wednesday by CA (the former Computer Associates) and the National Cyber Security Alliance (NCSA).

"We are already seeing hackers take advantage of community Web sites," Ron Texeria, executive director of NCSA, said in a statement.

Not only are the businesses in jeopardy, but many adults are putting themselves at risk for identity theft, too, according to Sam Curry, CA's vice president of threat management. "Just as terrorists look for the most number of victims by accessing aggregation points, malware writers look for that same in, on the Internet," said Curry. "The numbers in the study point to behaviors that easily infect computers."

The study reveals that 47 percent of adults who use social network sites are between 18- and 34-years old, and 53 percent are over 35. Of those adults who have access to a computer at work, 46 percent log onto social network sites from the office, making the workplace vulnerable to online security threats.

Although 57 percent who use social network sites admit to worrying about becoming a victim of cybercrime, they continue to divulge information that could put them at risk.

For example, 74 percent have provides some sort of personal information, such as their e-mail address, name, birthday, and even social security number.

Eighty-three percent of adults who use social network sites have downloaded content from another user's profile. Thirty-one percent have responded to phishy unsolicited email or instant messages.

"Social networks yet haven't focused on security applications, but they do have a responsibility to protect users, particularly if they are children," said Paul Stamp, security analyst at Forrester Research Inc.

Stamp said similar to the way social networking sites installed controls to protect consumers against online predators, MySpace, Facebook, YouTube and others will do the same to protect users against cybercriminals.

"Social networks have done quite a bit to educate their users about privacy and online safety," said eMarketer Inc. senior analyst Debbie Williamson.

News Corp's MySpace.com, for example, recently teamed up with Seventeen magazine to create a tip guide for parents and educators. Williamson believes it's in the social network's best interest to educate users, many of whom are teenagers or young adults.

The CA/NCSA study also reveals that education is long overdue. Fifty-one percent of parents with children who social network do not restrict their children's profiles to allow only friends to view, leaving their child's profiles unrestricted to potential predators. Similarly, 36 percent of parents surveyed do not monitor their children on social networking sites.

CA and NCSA received responses from approximately 2,163 adults, at least 18-years old. The research, conducted by Russell Research of New York, was conducted in August and September.