Invalid_viewstate exception

Discussion in 'ASP General' started by Paul Phillips, Nov 1, 2007.

  1. I have read many things about this but I haven't got a clear vision on what
    to do if anything about this.



    I have a system that tries to find holes in my web site. One of the things
    it has found and has been sent to me is

    an Invalid_Viewstate exception. I will provide the stack trace below. If
    you read down the stack trace it talks about "Invalid chararcter in a base-64
    string" error. After reading much about this have not found any resolution.
    I did read where one person said that people hit sites that require
    information and they sending bad or spam in hopes the site will forward the
    information on to an email and my site is capturing that because they also
    are changing the hidden field _VIEWSTATE which in turn causes this exception.
    I also read that the data that is being entered is not passing validation
    and there is a need to trap for it.



    so I still don't know what is exactly causing this error and should I worry
    about it.



    Here is the stack trace

    The error description is as follows :

    System.Web.HttpUnhandledException: Exception of type
    System.Web.HttpUnhandledException was thrown. ---> System.Web.HttpException:
    Invalid_Viewstate

    Client IP: 64.14.3.222

    Port: 40520

    User-Agent: Mozilla/5.0 (compatible; MSIE 7.0; MSIE 6.0; ScanAlert;
    +http://www.scanalert.com/bot.jsp) Firefox/2.0.0.3

    ViewState: ("blah blah blah" a bunch of encrypted data or something that I
    am just going to leave out)

    Http-Referer:

    Path: /folder/myGatherInformationPage.aspx. ---> System.FormatException:
    Invalid character in a Base-64 string.

    at System.Convert.FromBase64String(String s)

    at System.Web.UI.LosFormatter.Deserialize(String input)

    at System.Web.UI.Page.LoadPageStateFromPersistenceMedium()

    --- End of inner exception stack trace ---

    at System.Web.UI.Page.LoadPageStateFromPersistenceMedium()

    at System.Web.UI.Page.LoadPageViewState()

    at System.Web.UI.Page.ProcessRequestMain()

    --- End of inner exception stack trace ---

    at System.Web.UI.Page.HandleError(Exception e)

    at System.Web.UI.Page.ProcessRequestMain()

    at System.Web.UI.Page.ProcessRequest()

    at System.Web.UI.Page.ProcessRequest(HttpContext context)

    at
    System.Web.CallHandlerExecutionStep.System.Web.HttpApplication+IExecutionStep.Execute()

    at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean&
    completedSynchronously)



    Any help would greatly be appreciated.



    PaulP

    MCP
     
    Paul Phillips, Nov 1, 2007
    #1
    1. Advertising

  2. "Paul Phillips" <> wrote in message
    news:...
    > I have read many things about this but I haven't got a clear vision on

    what
    > to do if anything about this.
    >
    >
    >
    > I have a system that tries to find holes in my web site. One of the

    things
    > it has found and has been sent to me is
    >
    > an Invalid_Viewstate exception. I will provide the stack trace below. If
    > you read down the stack trace it talks about "Invalid chararcter in a

    base-64
    > string" error. After reading much about this have not found any

    resolution.
    > I did read where one person said that people hit sites that require
    > information and they sending bad or spam in hopes the site will forward

    the
    > information on to an email and my site is capturing that because they also
    > are changing the hidden field _VIEWSTATE which in turn causes this

    exception.
    > I also read that the data that is being entered is not passing validation
    > and there is a need to trap for it.
    >
    >
    >
    > so I still don't know what is exactly causing this error and should I

    worry
    > about it.
    >
    >


    Try asking this in the dotnet.framework.aspnet group. This one is for
    Classic ASP.

    --
    Anthony Jones - MVP ASP/ASP.NET
     
    Anthony Jones, Nov 2, 2007
    #2
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