Charles Sturt University cyber-security expert Doctor Tanveer Zia has warned the flaw, known as Shellshock or Bash Bug, may threaten larger servers to which many users may be connected.

"Unlike most computer attacks which target Windows-based systems, this vulnerability is found in systems powered with Unix or Linux and Apple's Mac OS X operating systems," he said.

"The bug does not seem to have affected Windows-based systems and Apple's iOS, the operating system used in iPhones and iPads."

Dr Zia said that from an end user's perspective the flaw has the potential to affect broadband routers and domestic smart appliances such as refrigerators, temperature sensors and surveillance systems that are connected to the internet.

"What this means to an average computer user is that a web server, which hosts a website holding users' personal information, may be affected by this vulnerability if that web server is running an un-patched version of the Unix or Linux operating system," he said.

"Unfortunately, many smart appliances are not designed to receive regular patches or updates if vulnerability is detected, unlike our smartphones which receive regular updates."

Dr Zia said users running Windows-based operating systems working locally do not need to worry, however the majority of users with inter-connected systems should do the following:

1. Keep an eye on updates from service providers and apply updates immediately.

2. Contact the broadband router or smart appliance manufacturers and ask for operating system updates

3. Be vigilant about phishing emails.

4. Consider changing passwords to important services.

5. Monitor signs for unusual activities in accounts.

6. Opt for two-factor authentication if it is available with the online business you deal with.

7. Avoid clicking on "dodgy" pop-up ads and unknown URLs.