Messaging security vendor Cloudmark on Monday announced a service designed to help ISPs and enterprises catch and clean PCs on their networks that have been infected by zombies.

More than 50% of the unwanted e-mail and 90% of phishing attacks come from zombie computers, those that have been infected by stealth malware that turns PCs into spam-sending machines, according to Jamie de Guerre, Cloudmark’s vice president of technology services. Most zombie-detection offerings on the market today look for these infected PCs by simply monitoring the volume of e-mail they send, because typically zombies blast out spam messages by the thousands.

However, zombie creators have caught on to this tactic and are tweaking their methods accordingly; many zombies are now working in trickle mode, sending only a few messages per hour in an attempt to evade detection, the company says.

Cloudmark’s new service takes advantage of analytics gathered from its Authority gateway e-mail security software monitoring outbound traffic, as well as information regarding zombie activity gleened from its network of ISP customers around the globe to identify hijacked PCs, de Guerre says.The company’s network of users proactively report to Cloudmark when they receive spam, offering real-time information that it can incorporate into its Authority software to help block unwanted messages.

With the anti-zombie service, ISPs can immediately spot and notify its subscribers that their PCs have been compromised, and network administrators can quarantine zombie PCs operating within the enterprise.   

---