"This Site May Harm Your Computer" is displayed by Google as a safe browsing advisory in its search results when it has found suspicious content during content crawling and indexing. The effect on traffic can be dramatic; especially for e-commerce sites.
I keep speaking with people where their online sales have dropped 50-100% within a few days of such a notice appearing.
The best thing of course is to try to avoid becoming listed as having suspicious content in the first place. That's where securing your web site, applications and related systems comes in. But you also want to find out as soon as possible if one of your web sites is being flagged as harmful, so that you can investigate the cause, fix the problems and remediate altered data.
What can you do in advance to help yourself and make sure you know as soon as possible?
- Register as the site owner (you—not your developers or hosting company)with:
- Check malware monitoring sites regularly:
- Google Safe Browsing http://www.google.com/safebrowsing/diagnostic?site=[yourhostname]
- McAfee SiteAdvisor http://www.siteadvisor.com/sites/[yourhostname]
- McAfee TrustedSource https://www.trustedsource.org/query/[yourhostname]
- Norton Safe Web http://safeweb.norton.com/report/show?url=[yourhostname]
- Stop Badware http://stopbadware.org/home/reportsearch
- Examine search results yourself (Bing, Google, Yahoo) using automated methods where possible (e.g. create a content/uptime monitoring alert which looks for the word 'harm' or 'malware' in each search engine's results page that will always include your web site).
- Install security widgets (such as McAfee SiteAdvisor or Norton Safe Web) in your own web browsers and visit your own web sites.
- Scan your own web site for malware using professional services, although there are some free tools available (e.g. Qualys Stop Malware or AVG Online Scan).
- Browse your own web sites using computers with a range of anti-malware (anti-virus) software installed and configured in the most paranoid mode.
- Build logging and monitoring into your web sites and applications which will detect unusual activity and unauthorised changes to files and other data.
Web site owners cannot register in advance with McAfee SiteAdvisor, but keep the URL handy so you can contact them if necessary.
But do remember, like other "reviews", organisations that display warnings about your site are under no obligation to respond or change the adverse status within any particular timescale. It's best not to become blacklisted in the first place.
Posted on: 21 September 2010 at 12:02 hrs