We've been protecting Google users from malicious web pages since 2006 by showing warning labels in Google's search results and by publishing the data via the Safe Browsing API to client programs such as Firefox and Google Desktop Search. To create our data, we've built a large-scale infrastructure to automatically determine if web pages pose a risk to users. This system has proven to be highly accurate, but we've noted that it can sometimes be difficult for webmasters and users to verify our results, as attackers often use sophisticated obfuscation techniques or inject malicious payloads only under certain conditions. With that in mind, we've developed a Safe Browsing diagnostic page that will provide detailed information about our automatic investigations and findings.

The Safe Browsing diagnostic page of a site is structured into four different categories:

  1. What is the current listing status for [the site in question]?

    We display the current listing status of a site and also information on how often a site or parts of it were listed in the past.

  2. What happened when Google visited this site?

    This section includes information on when we analyzed the page, when it was last malicious, what kind of malware we encountered and so fourth.   To help web masters clean up their site, we also provide information about the sites that were serving malicious software to users and which sites might have served as intermediaries.

  3. Has this site acted as an intermediary resulting in further distribution of malware?

    Here we provide information if this site has facilitated the distribution of malicious software in the past. This could be an advertising network or statistics site that accidentally participated in the distribution of malicious software.

  4. Has this site hosted malware?

    Here we provide information if the the site has hosted malicious software in the past. We also provide information on the victim sites that initiated the distribution of malicious software.

All information we show is historical over the last ninety days but does not go further into the past.   Initially, we are making the Safe Browsing diagnostic page available in two ways.  We are adding a link on the interstitial page a user sees after clicking on a search result with a warning label, and also via an "additional information" link in Firefox 3's warning page. Of course, for anyone who wants to know more about how our detection system works, we also provide a detailed tech report [pdf] including an overview of the detection system and in-depth data analysis.