Author Topic: Add option to Web Shield's URL Blocking feature to *not* show a placeholder  (Read 6938 times)

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Offline VanguardLH

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When content from a site gets blocked by the Web Shield's URL Blocking feature, a placeholder text area is positioned where that content would have been positioned.  This placeholder shows the content was blocked by Avast and gives the source for the blocked content.  However, this placeholder can get in the way. 

The blocked content, say an advertisement, might display in an area of the web page but permit the user to click on a Close or X button to reduce its size or get rid or or hide that content.  However, with the placeholder used by Avast, there is no way to run that script or event to eliminate or reduce the size of the ad space.  The result is that the web page remains unusable because the placeholder is obliterating some of its content and the placeholder cannot be removed.

Here is an example (not too bad here but I've hit far worse sites where Avast's placeholder wipes out most of the web page).  The blocked content is from doubleclick.net that I have added to the URL block list in the Web Shield:

http://arstechnica.com/software/news/2008/01/ie8-super-standards-mode.ars

I've attached a picture of what I see (in case you don't see it because you haven't blocked doubleclick.net by Avast).  I don't see a convenient means of getting rid of Avast's placeholder.  I don't even want it.  I would prefer a log be recorded showing web page statistics of time, URL of web page, URL of blocked content, and so on that I could review to see what got blocked if I ever cared about it.  There is no option in the URL Blocking feature to eliminate the placeholder.

I realize why Avast chose to insert the placeholder.  If it did not, positioning of other elements in the web page might get screwed up.  So Avast sticks in their placeholder that is probably based on the sizing attributes for the content it is replacing.  That does not account, however, for content that first obliterates a large area but provides an option to remove, hide, or resize it.  I'd rather suffer the problem of element rearranging on the web page than not to be able to see it at all.

The example I show here (because I just hit it and decided to ask now about this problem) is not so bad that I cannot use that web page to read its wanted content.  I have hit other sites where this placeholder is horrendous (because what it replaced was horrendous but Avast's placeholder is static whereas the original content could be moved out of the way).


Offline DavidR

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Personally I wouldn't be using the URL Blocking feature in the web shield, but in my adblocker, firewall or my Hosts file (using some sort of hosts file manager, etc.).

They would just block the content and no placeholder and are likely to be easier to manage blocked locations.
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Offline VanguardLH

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I don't like using a hosts file for filtering.  One, you allocate the responsibility to someone else and trust their "bad" list.  Two, this file is used to resolve hostnames, not domains.  You have to specify all the way to the hostname.  You can't use *.doubleclick.* (or just doubleclick.com and doubleclick.com).  Instead, the MVPs host file, for example, has over 50 entries just for DoubleClick because of all the hostnames they use.  Three, some sites have their nameserver accept any hostname and just return the same server's IP address.  That means there are a near infinite number of hostnames possible at that domain and you would never be able to list them all in your hosts file (and with no impact on the DNS-bypass local lookup).  Four, because someone else is compiling the list (since that's how you got it) then you have to periodically download an updated version to get their recent list of "bad" hostnames.

I've found adblockers to be generally too aggressive.  I have to keep adding exclusions or removing entries to use sites that I do want to visit.  I had to remove an entry from IE7Pro's adblocker, for example, just to use my own ISP's webmail site -- but only after taking a couple days to figure out why their site wasn't working.  In every case where a product included an adblocker, I eventually ended up disabling it.

I've used both the Comodo and OnlineArmor firewalls.  Both are excellent.  Both incur problems on my host.  Sometimes they are minor but I decide not to be nuisanced with them.  Sometimes the problems aren't so minor.  I have utilities, for example, that will dynamically load a file I/O driver which won't work with these firewalls.  Whitelisting their files and granting them full permissions still does not eliminate the interference from these firewalls (and others that I've tried).  Plus, I'm expert enough to not need the kitchen-sink protection that they offer (and expert enough to mess up the whole works and why I do daily incremental image backups and use virtual machines to isolate trials).  So I just use the simplistic Windows Firewall along with the one on my router.  Security is okay but not when it gets in my way.

I can, as an alternative, switch to using OpenDNS as my DNS server instead of using the one from my ISP.  You can select categories of sites to block and/or enter your own list of domains to block.  This works very well except for an artificat produced by using their DNS server: they sometimes insert an interstitial page to hide the blocked content (http://en.wikipedia.org/wiki/Interstitial_webpage).  The result is when you hit the Back button in your browser that you either get their interstitial page (and you have to hit Back again) or you are bounced back to the page you were at that you wanted to back away from (i.e., the interstitial page used a meta-refresh with zero timeout that pointed at the page to which you were led, so when you Back to that interstitial page then you're "refreshed" back to the target page).   Eventually this becomes a high enough repeated nuisance that I leave OpenDNS and return to using my ISP's DNS server.  Also, the freebie account at OpenDNS only lets me define 50 domains on which to block.  I already used up that quota and want to add more but can't.  I'm not interested in a pay account for something I can emulate locally with URL blocking.

So back to the URL blocking in Avast's Web Shield.  The RFE (Request for Enhancement) still stands.  I would like to see an option to NOT insert a placeholder text area -- just like you imply is available in the firewall and adblocker products.  I'd rather suffer the loss in element positioning on the web page (which is usually still readable) than to have some or most of it obliterated.
« Last Edit: June 05, 2009, 11:01:23 AM by VanguardLH »

Offline lukor

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Hi,
the actual place holder page is stored in Avast4/ENGLISH/HtmlData/Blocked.htm file and can be modified to better suite your needs. Wouldn't that help a bit?

Lukas.

Offline igor

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Erm... are you sure? (that it can be modified)

Offline VanguardLH

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I will try renaming the file.  It cannot be renamed while Avast is running even after stopping all the providers (Standard shield, Web shield, Network shield, and Outlook shield; other shields are installed but not configured to load).  I have Unlocker which alerted when I tried to rename the file (no handle found but rename failed, so it popped up).  It offers to rename the file on Windows startup so I opted for that (this is the same as in inuse utility from Microsoft and other such utilities that use the PendingFileRename (or some similar name) registry key to rename or delete files early during Windows startup).  I'll have to wait until I get around to rebooting my host to see if the rename worked.  Then I can see what Avast does when it cannot find this file.

Offline lukor

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Please, be carefull with the unlocker, if the file was opened for some reason and you would close the handles - something might go seriously wrong - I mean, the application that things the file is open may crash.

Anyway, this is not the case here, the file can be modified easily (when the avast! Self protection is turned off), but igor is right noting that it will get overwritten back during program update. I am not sure if the same will happen during VPS update as well.

Offline igor

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Unlocker won't help you here... anyway, yes, what I meant is that avast! setup may note the unauthorized change and replace the file back with the original one.

Offline Lisandro

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Unlocker won't help you here... anyway, yes, what I meant is that avast! setup may note the unauthorized change and replace the file back with the original one.
Igor is right... next repair/program update will restore back the original file.
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Offline chyron8472

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You shouldn't need Unlocker to delete/edit the Blocked.htm file. Here's what you should do:

1) Right-click your Avast! icon in the system tray and click "Program Settings..."
2) Click "Troubleshooting" in the menu list on the left.
3) Click on "Disable Avast self-defense module" to place a check mark next to it.
4) Click OK


5) NOW, edit Blocked.htm (usually in your "Avast4/ENGLISH/HtmlData/" folder.) by opening it in a basic text editor [in Windows, right-click it, click Open With -> Notepad (or Wordpad)]
6) Replace the entire contents of Blocked.htm with the following:

<html>
<head></head>
<body style="background-color:transparent"></body>
</html>

7) SAVE the file and EXIT the text editor.
8) Go back into Avast's Program Settings and REMOVE THE CHECK MARK previously mentioned from "Disable Avast self-defense module." This is VERY IMPORTANT.

The self-defense module prevents malicious users/programs from changing Avast's settings with the intention of breaking/subverting your anti-virus protection. You must turn it off to edit Avast's files. Make sure to turn it on again after you're done.

I don't remember if Avast once restored blocked.htm after my having deleted it, but I have edited mine to include the afformentioned html code, and it's been that way for many months now without being changed back by updates.
« Last Edit: July 02, 2009, 04:27:33 PM by chyron8472 »

Offline Lisandro

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I don't remember if Avast once restored blocked.htm after my having deleted it, but I have edited mine to include the afformentioned html code, and it's been that way for many months now without being changed back by updates.
It will be replaced at any program update or if you start repair installation option.
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Offline chyron8472

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lol well EDIT it then, don't delete it. My edited blocked.htm doesn't revert after updates, (though I haven't had to repair my install before... if repairing does replace blocked.htm, just repeat the process.)
« Last Edit: July 02, 2009, 06:46:12 PM by chyron8472 »

Offline VanguardLH

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From my first post:

"The blocked content, say an advertisement, might display in an area of the web page but permit the user to click on a Close or X button to reduce its size or get rid or or hide that content.  However, with the placeholder used by Avast, there is no way to run that script or event to eliminate or reduce the size of the ad space.  The result is that the web page remains unusable because the placeholder is obliterating some of its content and the placeholder cannot be removed."

Replacing one placeholder (with Avast's content) with another placeholder (with blank/transparent content) doesn't seem to solve the problem.  Both are static.  They will be sized to whatever is the area for the replaced content.  They won't resize (or start with an initial size) as would the original content that can be closed or reduced in size.  There are no controls in either of these HTML files for, say, clicking on an "X" or "Close" button that would reduce the placeholder to whatever reduced size capable by the original content.  Also, where the original content could get closed, these placeholders would remain to block the underlying page content.

As to the BLOCKED.HTM file getting replaced by program updates, the About dialog says my version is from back in February.  So, yes, a modified copy of this file might survive for many months but on the next program update it would get replaced.  I haven't kept track of how often Avast gets program updates.
« Last Edit: July 02, 2009, 08:35:19 PM by VanguardLH »