AVG Antivirus sending me lots of unwanted traffic and how I dealt with it

I wrote last month about an enormous amount of traffic being directed to this blog all of a sudden. The culprit is the latest version of AVG antivirus which installs a module called ‘Linkscanner’. Essentially what this does is when someone searches Google for example, Linkscanner will automatically check every link in the results. The Register have written about it a couple of times.

This is bad because it seriously skews my statistics for one and very bad because it is chewing up a lot of my available bandwidth. So what is one to do?

As I noted previously, AVG uses a few unique user agent strings. These can be used in a .htaccess file to deny access to Linkscanner or as in my case redirect the request to a certain page. Unfortunately my ability with using regular expressions is pretty limited to say the least but while browsing a discussion about Linkscanner on reddit.com last night someone posted a solution. That someone was none other than Pádraig Brady who is a frequent contributor to the Irish Linux Users Group.

Rather than post Pádraig’s solution here I will link to it instead. However instead of directing AVG users back to the AVG site as Pádraig’s example does – I redirect them to a custom page I made earlier. I was going to link to my custom page but since I will be using it to keep a tally of AVG hits I decided not to link to it here.

To get an idea of how much extra traffic is generated as a result of Linkscanner consider that this site is relatively light on traffic but in the two hours since I started redirecting AVG users, the page mentioned above has been hit over 240 times!

Bad AVG, very bad.

Jun 28th, 2008 | Posted in Blog, General, Networking, Security, Technical, Web
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  1. Jun 28th, 2008 at 20:41 | #1

    Over 18k hits from the SV1 user agent today alone. Bastards. That possibly explains the jump in visitors, but there’s also been a jump in Adsense clicks too so it can’t all be automated bots.

  2. Jun 28th, 2008 at 20:45 | #2

    Hi Donncha – Maybe I should put up some ads so ;)

    I’m still amazed that AVG think there is nothing wrong with what they are doing. Technically I suppose they are doing nothing wrong as such but the situation stinks. :|

  3. Jun 29th, 2008 at 15:24 | #3

    I enabled those rules this morning and redirected to a local file. Looks like only some of the bots follow the redirect for some reason. Not sure why.

  4. Jun 29th, 2008 at 15:43 | #4

    That’s curious. I know that with some of the AVG user agents actually begin with the words ‘User Agent’ I had those filtered by my proxy already.

  5. Jun 29th, 2008 at 18:20 | #5

    From the logs, it’s the “User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1)” bot that redirects. The others don’t. Seems to be working well though. I’ll post figures in a few days time!

  6. Jun 30th, 2008 at 12:52 | #6

    It works very well. It will be interesting to see your stats. I’m racking up about 400 per day.

  7. Jul 3rd, 2008 at 21:09 | #7

    I wonder why my post didn’t send a pingback? That last one is a spam site.. Did you get many click throughs?

  8. Jul 3rd, 2008 at 23:33 | #8

    Donncha -

    That is very strange! Just deleted the spammy one.

    I only found out you linked to my entry via a google alert at 17:35 yesterday (Thursday).

    I never got any notification of any track/pingbacks even though WP is configured to allow them. I got no notification of the one I just removed either.

    As of half an hour ago, Both Awstats and Firestats both show three visitors referred from your post.

    There are a few things that could have caused it that I would rather not discuss here so if you need more info mail me directly.

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