I run Avast 6.x. The only thing I see in my firewall log is Avastsvc.exe which is used for Avast’s web shield and because I chose to log all events it generates.
BTW - Avast’s web shiield uses a localhost proxy that connects to port 12080 from your browser. It then connects to the Internet from localhost ports in the 12000 - 12999 range to the orignal destination port which is usually port 80. It only does that for http traffic. It does not do that for https, tcp, or anything else your browser might be connecting to.