Get the Whitepaper called Socket Capable Browser Plugins Result In Transparent Proxy Abuse.
You can download it from the following link: https://packetstormsecurity.com/files/download/75627/TransparentProxyAbuse.pdf
Source: https://packetstormsecurity.com/files/75627/Socket-Capable-Browser-Plugins-Result-In-Transparent-Proxy-Abuse.html