The Australian Communications and Media Authority (ACMA) is detecting some 30,000 infected computers that form Australian-operating botnets each day.
A government cybercrime report
(Credit: House of Representatives)
The bulk of botnets that infect users' computers are known as zombies, which are drone machines that criminals use to attack targets or generate mass spam campaigns.
ACMA e-security manager Bruce Matthews said it is unknown how many of those reported are unique.
"We would see between 20,000 to 30,000 [bots] reported a day operating in Australia," Matthews told ZDNet Australia. "It does not necessarily mean the number is getting worse."
"Not only do infected user machines cause problems for other users, but it usually means the [victim] has had their personal information stolen too."
He also noted that botnet masters, which control botnets, are discovered and shut down in Australia each year.
Matthews leads the Australian Internet Security Initiative (AISI), started in 2005, which collates botnet behavioural data into a report that is then delivered to 84 internet service providers. The data is used to track-down offending machines and inform respective users.
He suspects most victims of identity theft in Australia would have lost data through a zombie computer. The Australian Federal Police estimates that identity fraud costs Australia a staggering $4 billion a year.
However, Matthews said the infection rate is less than international averages.
The most prolific infections detected by the AISI are Conficker, Sality and generic trojans, according to Matthews.