Zombie attacks cost ISPs dear

Zombie botnets of up to 100,000 infected machines now being openly advertised for hire

Security firm StreamShield Networks introduced a tool this week which it claims will help ISPs better understand the real cost of botnets and zombie infections on end-user machines.

Such threats are estimated to cost ISPs around the world $500m every year in excess traffic and customer churn alone, the company claimed.

"Botnets and zombie infected PCs are a serious industry-wide issue," said Geoff Bennett, director of product marketing at StreamShield.

"Ironically, even though innocent broadband and cable users are the ones that get infected with zombies, it's the ISPs that end up carrying the cost.

"StreamShield studies show that botnets are costing ISPs millions every year in wasted off-net bandwidth, customer churn, network operations and helpdesk time."

The firm's ZombieCalc tool allows an ISP to identify and automatically quarantine infected subscribers, and protect them against future malware infection.

"The subsequent subscriber quarantine process can be fully automated, which eliminates the operational cost of ongoing zombie detection and decontamination, " the company said.

"The quarantine process can include the opportunity to provide the subscriber with desktop content security software, or to upsell the subscriber to a safe internet service."

The Federal Trade Commission estimated in 2005 that up to 150,000 PCs were being hijacked daily to be used in criminally motivated denial of service, spamming and phishing attacks.

The problem has continued to grow with botnets of up to 100,000 infected machines now being openly advertised for hire on internet newsgroups.

Analyst firm Gartner estimated recently that up to 70 per cent of all spam is generated by zombie machines.