Kaspersky Labs set up a Wi-Fi honeypot on its stand and found that 55 per cent of Wi-Fi networks at the event did not use data encryption.
The security firm said the results were unacceptably high even if the number of available public access points was factored in.
"Hackers are attracted to such exhibitions by the opportunity to break in to the networks of companies taking part," said David Emm, senior technology consultant at Kapsersky Labs.
"Almost all firms that exhibit at the show set up their own local networks. Unfortunately, they are typically set up quickly and with low security settings. "
Honeypots are automatic collection stations set up by security researchers to measure the effectiveness of a security system.
In some cases they are set up to look like corporate networks to encourage people to hack them in order to study the techniques used.
In a similar experiment F-Secure set up a Bluetooth honeypot at the show, which attracted over 450,000 visitors.
"At any given time we would see more than 100 Bluetooth devices wandering within our range," said Mikko Hyppönen, chief research officer at F-Secure.
"The grand total was 12,500 unique devices that had Bluetooth, had it enabled, and had it visible. Unbelievable."
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