Attacks on PCs by botnets – the so-called zombie networks - are becoming more of a problem, with more than a million hosts already controlled by hackers.

That’s according to the the Honeynet Project, an organisation that sets up PCs to be deliberately affected, which found that “The threat posed by botnets is probably worse than originally believed”.

The research published in a White Paper, Know your enemy: Tracking botnets found that the threats can’t be under-estimated as they pose “a severe threat” to the wider community. It's more bad news for PC users, two months ago, the Honeynet Project found that hackers were concentrating almost exclusively on Windows machines.

The project tracked more than 100 active botnets, including one containing 50,000 compromised "zombie" machines.

The report pointed out that "more then one million hosts are compromised and can be controlled by malicious attackers" although it warned that this was a probable underestimate. The company also made an estimate as to the scope of DDoS attacks. In the tracking period, from November 2004 to January 2005, Honeynet detected a staggering 226,585 IP addresses joining at least one of the channels being monitored

The Honeynet Project believes that there is much more work needed in keeping botnets at bay. In the report, it pointed out the range of potential damage. “Our research shows that some attackers are highly skilled and organized, potentially belonging to well organized crime structures. … "Since botnets pose such a powerful threat, we need a variety of mechanisms to counter it."

Ominously, the report concluded by pointing out that "more research in this area is needed, attackers don't sleep. As these threats continue to adapt and change, so to must the security community."