My site's error log is filled with the errors related to ScriptResource.axd

My 开发者_开发百科Site's error log is filled with these errors:-

This is an invalid script resource request. Invalid viewstate. Invalid character in a Base-64 string. Invalid length for a Base-64 char array.

All these errors are appearing at least 100 times a day.

After doing some RnD on internet i have done following things:-

1- define machine key in my web config. 2- created robots.txt file and add ScriptResource.axd file in that.

Can some one guide me what I am missing or doing wrong.

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1. First Possible Reason
   I have see some crawlers that remove the verify key on the end of the files, or convert it to small case, so this have as result to get this error.

2. Second Possible Reason
   Some one test and search your pages for weak points and entry ways to your back data.

On the log you can see how they call the ScriptResource.axd and what is the problem on the key. And check what ip make this calls - is the same ?

Some reference.

"Padding is Invalid and cannot be removed" exception on WebResource.axd

CryptographicException: Padding is invalid and cannot be removed and Validation of viewstate MAC failed

one more, I do not think that its need to add ScriptResource.axd on robots and remove it from search (I mean that this is not actually the problem) - how ever its not bad idea.