Credit card details could be exposed after a visit to an infected website.
Infected websites accessed by internet users could put
Aussie credit card details at risk when using legitimate e-commerce sites later.
Security organisation Norton Symantec explains that infected sites can lead to the installation of keystroke loggers on users' computers.
This can put their personal information in jeopardy later as, when they type it in to a secure website, the keys they press could be transmitted to the people who distributed the virus.
Natalie Connor, a spokesperson for the firm, tells The Age that many people may be unaware of the risks they face online.
"What people don't realise is, when you type in a website, you're bringing down information on a page and with it could be malware," she says.
It is this malware that poses a threat to Aussie credit card details and other items of personal information.
Norton Symantec adds that, across each of the 100 most threatening sites, around 18,000 instances of malware, spyware or viruses exist.
A survey conducted by the firm earlier in the year found that more than half of small businesses in Australia and New Zealand have suffered a breach of data security due to hacking, theft or data loss.
Written by Emma North