Someone (probably a bot) sent a request with the following URL to my ASP.NET 4.0 web forms application (running on IIS 7.0):
http://ipaddress-of-my-applications-domain/bla1.bla2.bla3.bla4.bla5:)
This caused an System.Web.HttpException. I received a logging email from ASP.NET HealthMonitoring I had configured, telling me:
A potentially dangerous Request.Path value was detected from the client (:).
Stack trace was:
System.Web.HttpRequest.ValidateInputIfRequiredByConfig()
System.Web.HttpApplication.PipelineStepManager.ValidateHelper(HttpContext context)
Why is a colon in the URL "potentially dangerous"? What dangerous things can be done with such a URL? Do I have any security hole here I am not aware of?
Thanks for explanation in advance!
Edit
I've tested that a colon in a query string (like http://mydomain.com?Test=9:)) does not cause this exception.