Google has launched a campaign to notify operators of compromised Web sites that they need to do some tidying up.“To help protect users against malware threats, Google has built automated scanners that detect malware on Web sites we've indexed,” Google said in a blog posting. “Pages that are identified as dangerous by these scanners are accompanied by warnings in Google search results, and browsers such as Google Chrome, Firefox, and Safari also use our data to show similar warnings to people attempting to visit suspicious sites.”Operators whose sites are identified as hosting malware will receive an email from Google containing snippets of the offending code and advising them to sort it out. Only webmasters who are registered with Google will get these notifications.“While it is important to protect users, we also know that most of these sites are not intentionally distributing malware,” Google said. “We understand the frustration of webmasters whose sites have been compromised without their knowledge and who discover that their site has been flagged. We proactively offer help to these webmasters: we send email to site administrators when we encounter suspicious content, we provide a list of infected pages in Webmaster Tools, and we maintain a service that allows webmasters to notify us when they have cleaned their sites.”Legitimate sites that have been corrupted by hackers are a leading source of malware infections. Hackers find loopholes in a site’s coding which allow them to inject malicious code into the site’s pages. Users clicking on these embedded malicious links can be redirected to other sites where their computers will be infected.A recent study by MessageLabs found that 80% of domains being blocked as deliverers of malware were in fact compromised, legitimate Web sites.