Weeeeeell...... everyone's gonan hate me now as I'm having a moan!! But look, I really think that Alwil should decide whether to make a url blocker and call it solid and purposeful, or just drop it. What's the pont in a half hearted feature? I've got an ad blocker in Firefox, and Firefox is my default browser. Doesn't matter if stuff is tunneling thru IE, you know! But let's forget URL block for a moment as I've moved my mind more onto the fact that we have unscanned http traffic.
It might be naive to not expect a M$ product to not channel traffic quietly via IE, but if this kind of back door is going to open up I'm tempted to just cripple IE so it can't network. I already have "ietab" setup for Firefox, but why do I have to get drastic.
Technically, it's interesting. If I force IE 7 to use 12080 as a proxy, then very clearly the MSN advert traffic called for Messenger is pulled via Avast, via 12080, and blocked. It all relies totally on IE - I used the contents of my IE temp folder to work out the urls to block! ;-0) I guess that in the absence of a specified proxy/port, IE is just using arbitrary ones!! Conversely, I gather that Avast can force ALL traffic via one route when not transparent. Choices choices.
Forget deciding that it either is or is not a flaw in Avast. The fact is that the transparent operation of web scanner is not set by default to catch and scan certain traffic related to (arguably) the most common browser and (arguably) the most common IM client. (I don't know why Zone Alarm doesn't care either). Someone somewhere is going to exploit this to sneak some virus disguised as an MSN component past the protection software, right in to the system through IE, and 9 out of 10 users will have been believing they had these bases covered with their AV software. I can't currently identify the ports being used, but as I said I really cannot see why this is not pre-set in the Alwil product, to be quite honest. I'm sure nobody thinks I have a good point, but there you go.....
I'm going for a lie-down!! Ha ha!