Since 2005, Safe Browsing has been protecting users from harm on the Internet, and has evolved over the years to adapt to the changing nature of threats and user harm.
Today, sites in violation of Google’s Malware, Unwanted Software, Phishing, and Social Engineering Policies show warnings until Google verifies that the site is no longer harmful. The verification can be triggered automatically, or at the request of the webmaster via the Search Console.
However, over time, we’ve observed that a small number of websites will cease harming users for long enough to have the warnings removed, and will then revert to harmful activity.
As a result of this gap in user protection, we have adjusted our policies to reduce risks borne by end-users. Starting today, Safe Browsing will begin to classify these types of sites as “Repeat Offenders.” With regards to Safe Browsing-related policies, Repeat Offenders are websites that repeatedly switch between compliant and policy-violating behavior for the purpose of having a successful review and having warnings removed. Please note that websites that are hacked will not be classified as Repeat Offenders; only sites that purposefully post harmful content will be subject to the policy.
Once Safe Browsing has determined that a site is a Repeat Offender, the webmaster will be unable to request additional reviews via the Search Console for 30 days, and warnings will continue to show to users. When a site is established as a Repeat Offender, the webmaster will be notified via email to their registered Search Console email address.
We continuously update our policies and practices to address evolving threats. This is yet another change to help protect users from harm online.
Source: Google Online Security Blog: Protecting users from repeatedly dangerous sites
