"Even if a user is confident that his/her computer is securely protected, an infected USB stick from friends or family could result in data loss," said Kaspersky Lab, the company that commissioned the survey.
The survey conducted in May 2012 found that 32% of users reported attacks resulting from such infections.
The most popular method of committing cybercrime via the internet and criminals employ a variety of tools to lure victims, but the universal use of flash drives along with high storage capacity has made them attractive malware distribution channels.
This is particularly worrying said Kaspersky, given that most people store personal information on their devices.
"Along with cyber-threats, users worry about unauthorised access to their personal data and the devices it is stored on. According to the survey, this problem affected 14% of desktop and laptop users, 12% of tablet owners and 10% of those respondents with smartphones."
The company recommends encryption of valuable information to protect personal data or sensitive files.
Users who access the internet on unsecured wireless networks should be vigilant as hackers could potentially intercept information.
The survey found that 46% of smartphone users, 48% of tablet owners, and 29% of those with laptops make use of free Wi-Fi.
"This rather worrying statistic demonstrates that users clearly underestimate the dangers of free Wi-Fi. When it comes to wireless networks, it is very easy to avoid the threat of your data being intercepted by only using secured hot-spots," said Kaspersky.
Kaspersky had previously noted that South Africans are not a global priority for hackers, but as more users come online, they may be targeted for banking details or other financial information.
"The top three most vulnerable programs for Windows PCs are Adobe Acrobat Reader, Oracle Java and Adobe Flash," the company said.
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