Wondering how users' machines keep getting all those nasty infections and data keeps leaking out, despite all the defenses IT can erect?

A study released Tuesday by InsightExpress, an independent market research firm, may shed some light on the problem.

Forty-four percent of mobile users questioned in a survey this spring said they open e-mails and attachments from unknown or even suspicious senders. The study also showed that one-third of mobile users access unauthorized wireless connections, whether they're hijacking a neighbors' wireless connection or using unsecured hotspots at a coffee shop or in a public park.

The study was commissioned by Cisco Systems and the National Cyber Security Alliance.

"Businesses are increasingly entrusting more and more employees with access to corporate information anywhere outside of the office," said Ben Gibson, a director at Cisco, in a written release. "After all, embracing mobility and truly leveraging the power it gives businesses -- agility, access, responsiveness, efficiency -- requires protecting and educating employees to prevent them from undermining this value. This is a role IT can and should play more proactively than they traditionally have in the past."

According to the study, 73% of mobile users said they are not always aware of security threats and best practices when working on the go. Although many said they are "sometimes" aware, another 28% admitted they "hardly ever" consider security risks and proper behavior. Some even said they "never" consider safety best practices and didn't know they needed to be aware of security risks.

When questioned about why they're so lax about wireless security, the top answers included, "I'm busy and need to get work done," and "It's IT's job, not mine."

InsightExpress surveyed 700 mobile workers in seven countries that have widely adopted wireless technologies -- the United States, the United Kingdom, Germany, China, India, South Korea, and Singapore.

Ron Teixeira, executive director of the National Cyber Security Alliance, offered up several safety tips that IT shops should consider implementing:

• Use strong passwords that are changed every 90 days;
• Update antivirus and anti-spyware programs regularly;
• Download necessary patches regularly;
• Back up all important files and data;
• Encrypt sensitive data, and
• Have an emergency response plan for wireless security breaches.