Looking at a client's site today that was reporting that their event log was growing like crazy - 50-90 pages in hours.
When I looked at the log it was for a url that does not exist on the site /DesktopModules/LP_HTMLMacro/ImageChallenge.captcha.aspx
And it was from this agent / bot -- msnbot-media/1.1 (+http://search.msn.com/msnbot.htm)
A couple of things though caught my eye - the event error was for a badly formed link
System.FormatException: Input string was not in a correct format.
at System.Number.StringToNumber(String str, NumberStyles options, NumberBuffer& number, NumberFormatInfo info, Boolean parseDecimal)
at System.Number.ParseInt32(String s, NumberStyles style, NumberFormatInfo info)
at DotNetNuke.UI.WebControls.CaptchaControl.GenerateImage(String encryptedText)
And not because the url did not exist - so I did some testing.
There is no ImageChallenge.captcha.aspx in the module - but what i found more odd was that in fact it dont MATTER what you put into the url ... all it needs to do is end in captch.aspx for the system to start trying to process the url thru the image captch control - for example:
a url like //www.dnnsoftware.com/Desktopqweules/HTMLNotHereMaasdcro/Imaasdasdrnge.captcha.aspx will bypass all the normal bad url checks not returning a page not found - but possibly trigger the creation of an error event in the event log - instead of showing a URL not found message.
Anyone got any thoughts or ideas on how to deal with this - and i guess stop it filling up the clients event log.