title: ScriptResource error: am I being hacked?
body: <p>I keep getting errors like this on one of my sites. It tends to happen randomly throughout the day any for periods in the night when I would not expect users on the site. </p>
  
  <p>It is always from different ip addresses</p>
  
  <blockquote>
    <p>System.Web.HttpException: Invalid
    viewstate. at
    System.Web.UI.Page.DecryptStringWithIV(String
    s, IVType ivType) at
    System.Web.UI.Page.DecryptString(String
    s)</p>
  </blockquote>
  
  <p>or </p>
  
  <blockquote>
    <p>System.Security.Cryptography.CryptographicException:
    Padding is invalid and cannot be
    removed. at
    System.Security.Cryptography.RijndaelManagedTransform.DecryptData(Byte[]
    inputBuffer, Int32 inputOffset, Int32
    inputCount, Byte[]&amp; outputBuffer,
    Int32 outputOffset, PaddingMode
    paddingMode, Boolean fLast) at
    System.Security.Cryptography.RijndaelManagedTransform.TransformFinalBlock(Byte[]
    inputBuffer, Int32 inputOffset, Int32
    inputCount) at
    System.Security.Cryptography.CryptoStream.FlushFinalBlock()
    at
    System.Web.Configuration.MachineKeySection.EncryptOrDecryptData(Boolean
    fEncrypt, Byte[] buf, Byte[] modifier,
    Int32 start, Int32 length, IVType
    ivType, Boolean useValidationSymAlgo)
    at
    System.Web.UI.Page.DecryptStringWithIV(String
    s, IVType ivType) at
    System.Web.UI.Page.DecryptString(String
    s)</p>
  </blockquote>
  
  <p>They happen in this page:</p>
  
  <pre><code> ScriptResource.axd?d=VVe1O4rzLSI9hB5nRzBXZxUYTQz6ylDTL9djGR
  </code></pre>
  
  <p>The site users Ajax and runs on .NET 3.</p>
  
  <p>Is this someone trying to hack into the site? Is it an error with the html on the site?</p>
  
  <p>Any ideas?</p>