Why is your site flagged?

Here are reasons why your website can be flagged with the "This site may harm your computer" warning in Google search results:

1. Your site was hacked. This is the most common reason for the badware flag. If someone can trick your server into allowing them to modify files in your site, they can insert malicious code into your web pages or database tables, or they can alter your .htaccess or your HTML or JavaScript code so your site automatically redirects visitors to a malicious site.

2. A site other than yours got hacked, but it is affecting the content on your pages. Let's say your pages have normally harmless iframes or JavaScript that are pulled into a visitor's browser from the other website by using the property (in the HTML code) "src=http://othersite", or they use PHP code that resides on another website but is included into your pages before being served, with a PHP include(). If the other website gets hacked, your pages can turn dangerous, too, if the content that the other site was supposed to be sending out (advertisements, hit counters, top 10 lists ...) gets replaced by viruses, spyware, or other bad things. Whenever you use content from another website on your pages, you are dependent on that other site staying clean.

3. Your pages trigger the loading of Flash .swf files that are scripted to do malicious things or that are out of date and exploitable. Flash advertising is a common problem area.

4. (Your site contains an outlink to another site that has badware on it.) This was once a major reason for being flagged. That might not be true anymore, but it is still worthwhile to check your outlinks to make sure you are not linking to malicious sites, or to a site that got hacked and has turned malicious.

StopBadware and Google describe the criteria they use to determine whether a website is contributing to the badware problem.

The Firefox 3+ and Chrome browsers use data from the Google Safe Browsing Service to warn users about suspected malicious sites. If your site is flagged in Google search results, Firefox 3 users are getting a warning that says, "Reported Attack Site!", and they are blocked from going there.