
Irresponsible behaviour, using peer-to-peer applications, instant messaging software, USB sticks and incorrectly configured computers can all contribute to network risks, according to Sophos.
"It's concerning how many companies are unaware of non-compliant machines being used on their network, even though they may be permanently connected," said Graham Cluley, senior technology consultant at Sophos, in a statement.
Remote workers were another big concern for company bosses, with 31 percent of respondents feeling they are the biggest threat, compared to a quarter that considers external contractors or guest workers the greatest security risk.
"Mobile workers and guests can be a real bugbear for IT administrators trying to safeguard corporate networks, particularly when they're using different devices, security software and operating systems. They can inadvertently expose the network to a myriad of security threats," Cluley added.
The global survey questioned 208 organisations.