Cisco observed 400 hosts were infected on daily base and more than 2,700 URLs have been used in a multistage attack against websites running older OS versions. The victims were located mainly in the United States, Germany and Spain according Cisco researchers. The attackers exploited well-known vulnerabilities not patched by the administrators. Old versions of OSs are no more under maintenance, every flaw still present will be never fixed for the interruption of updates release and attackers can benefit of this circumstance if they are able to identify and exploit these bugs.”]
Source: http://securityaffairs.co/wordpress/23385/cyber-crime/cisco-large-scale-attacks-vs-servers.html