Firefox to US$7,500 cash reward) to researchers who discover severe security holes in Firefox. Official guidelines for handling security vulnerabilities discourage early disclosure of vulnerabilities so as not to give potential attackers an advantage in creating exploits. Because Firefox generally has fewer publicly known security vulnerabilities than Internet Explorer (see "Comparison of web browsers"), improved security is often cited as a reason to switch from Internet Explorer to Firefox. "The Washington Post" reported that exploit code for known critical security vulnerabilities in Internet Explorer was available for 284 days in 2006. In comparison, exploit code for known, critical security vulnerabilities in
Internet Explorer issue was released the following day with the Security Update for Internet Explorer KB960714, on Microsoft Windows Update. In 2011, a report by Accuvant, funded by Google, rated the security (based on sandboxing) of Internet Explorer worse than Google Chrome but better than Mozilla Firefox. A more recent browser security white paper comparing Google Chrome, Microsoft Edge, and Internet Explorer 11 by X41 D-Sec in 2017 came to similar conclusions, also based on sandboxing and support of legacy web technologies. Internet Explorer has been subjected to many security vulnerabilities and concerns: much of the spyware, adware, and computer viruses across