From MozillaZine Knowledge Base
As part of its Safe Browsing feature, Mozilla Firefox keeps track of a list of malware to compare against data the user downloads. In the event the user downloads known malware, a warning can be displayed. This preference determines whether to enable these malware checks.
Possible values and their effects
Download data about malware and use it to screen downloads. (Default)
Do not download malware blacklists and do not check downloads.
A checkbox labeled “Block reported attack sites” is located under Tools → Options → Security.
In SeaMonkey 2.18 and later, this checkbox is located in the Edit → Preferences → Privacy & Security main tab.
First checked in
Has an effect in