Security outfit Comodo has become the first vendor to offer ‘guaranteed’ malware removal from PCs protected by its software.

The ‘A-VSMART’ warranty costs $79 (£40) per PC, per year, which the company claims removes the burden on a non-expert user of having to remove complex malware types such as spyware and rootkits, which can be tricky to get rid of using automated routines. Instead, each subscriber will be given access to a remote Comodo engineer to do the job manually on a 24/7 basis, on an incident-by-incident basis.

A more expensive A-VSMART Warranty Plus, costing $119 (£60) per year will, in addition, offer expert installation of the Comodo Firewall Pro software, which uses whitelisting to limit the applications running to those in a Comodo-defined database.

Because an application can still be installed by a user who decides, possibly in error, to overrule the whitelisting, the warranty offers the manual system cleaning option for such mistakes.

“Most AV software is detection based, meaning that the application is allowed to gain access to the PC and then removed. That model has a few problems. The Comodo A-VSMART approach is prevention based, which means that the software does not remove malware largely because malware does not get on a machine,” said Comodo’s Judy Shapiro.

Most rivals were reluctant to criticise the business model of another security company when asked for comment, but at least one did raise questions about the concept.

“We think it's better to continue to develop and extend our technologies than to offer an insurance policy to anyone unfortunate enough to become the victim of an attack,” said David Emm of Kaspersky.

In 2006, Comodo’s free firewall was one of only two out of twenty-one to gain an ‘excellent’ rating during tests by security expert, David Matousec.

Assessing the effect on PC performance of the Comodo security design is hard – all security software running on a client PC will introduce some latency. However, one potential problem with software firewalls in the past has been their intrusiveness, both in terms of interrupting the user with dialogs and interfering with connectivity.

If Comodo can overcome these worries, then its paid-for service could be the start of a useful alternative to the traditional anti-malware scanner based on signature updates, and one of the first to use whitelisting in mainstream security.