Possible DoS attack in referers list

[E150]

Hi all,

I'm copying here a previous mail I sent to one of the maintainers of pixelpost site:

I've read some posts about mysql queries that take long time (those getting the list of referers) and high visitor counts, so I've been investigating this issue a bit. Note that I'm not currently using the latest version of pixelpost.

The fact is that there are some undesirable bots that are sending a lot of traffic to the site, increasing the visitors and referers count, so when someone hits the referers link, mysql has to count all the hits for every one of these sites that are generating traffic to pixelpost (generally viagra sites and the like...).

These mysql queries are _VERY_ time consuming, so the result is the CPU being 100% during long periods of time, leaving the server almost unusable. I tried to block the IP's from these machines but then new IP's generate more traffic. I think this is a known bug by many people, since they're googling for strings like "referers last seven days". Maybe this is a known bug for you too, I only wanted to know if you are concerned about it and if it's fixed on the latest versions.

I think an easy solution to this would be to limit the referers list to say, the 10 or 20 first referers. Anyway, I've been told that this issue will be probably fixed in the new version of pixelpost.

[Joe[y]+]

yes. we're discussing the best solution right now.

i read your email and i agree. limiting referers is a good idea and a simple solution.

[riken]

Originally Posted by E150

Note that I'm not currently using the latest version of pixelpost.

Up to version 1.3 there was a problem with load when looking up refereres in the database. In 1.4 indexes were added so that the load on the database would be lower.

So upgrading to 1.4.1 should fix your problem of high system load on the mysql server. And the next version has more stuff for handling spammers.

[Joe[y]+]

sorry. i misread that as you ARE using the most uptodate version.

any problems you encounter with older versions of pixelpost we cannot fully help with as it is much easier to work with our current version to save confusion.