ASP.NET CSRF 解决【网摘】

http://stackoverflow.com/questions/29939566/preventing-cross-site-request-forgery-csrf-attacks-in-asp-net-web-forms

1.在Master页面添加以下代码

C#

public partial class SiteMaster : MasterPage
{
  private const string AntiXsrfTokenKey = "__AntiXsrfToken";
  private const string AntiXsrfUserNameKey = "__AntiXsrfUserName";
  private string _antiXsrfTokenValue;

  protected void Page_Init(object sender, EventArgs e)
  {
    //First, check for the existence of the Anti-XSS cookie
    var requestCookie = Request.Cookies[AntiXsrfTokenKey];
    Guid requestCookieGuidValue;

    //If the CSRF cookie is found, parse the token from the cookie.
    //Then, set the global page variable and view state user
    //key. The global variable will be used to validate that it matches
    //in the view state form field in the Page.PreLoad method.
    if (requestCookie != null
        && Guid.TryParse(requestCookie.Value, out requestCookieGuidValue))
    {
      //Set the global token variable so the cookie value can be
      //validated against the value in the view state form field in
      //the Page.PreLoad method.
      _antiXsrfTokenValue = requestCookie.Value;

      //Set the view state user key, which will be validated by the
      //framework during each request
      Page.ViewStateUserKey = _antiXsrfTokenValue;
    }
    //If the CSRF cookie is not found, then this is a new session.
    else
    {
      //Generate a new Anti-XSRF token
      _antiXsrfTokenValue = Guid.NewGuid().ToString("N");

      //Set the view state user key, which will be validated by the
      //framework during each request
      Page.ViewStateUserKey = _antiXsrfTokenValue;

      //Create the non-persistent CSRF cookie
      var responseCookie = new HttpCookie(AntiXsrfTokenKey)
      {
        //Set the HttpOnly property to prevent the cookie from
        //being accessed by client side script
        HttpOnly = true,

        //Add the Anti-XSRF token to the cookie value
        Value = _antiXsrfTokenValue
      };

      //If we are using SSL, the cookie should be set to secure to
      //prevent it from being sent over HTTP connections
      if (FormsAuthentication.RequireSSL &&
          Request.IsSecureConnection)
      {
        responseCookie.Secure = true;
      }

      //Add the CSRF cookie to the response
      Response.Cookies.Set(responseCookie);
    }

    Page.PreLoad += master_Page_PreLoad;
  }

  protected void master_Page_PreLoad(object sender, EventArgs e)
  {
    //During the initial page load, add the Anti-XSRF token and user
    //name to the ViewState
    if (!IsPostBack)
    {
      //Set Anti-XSRF token
      ViewState[AntiXsrfTokenKey] = Page.ViewStateUserKey;

      //If a user name is assigned, set the user name
      ViewState[AntiXsrfUserNameKey] =
             Context.User.Identity.Name ?? String.Empty;
    }
    //During all subsequent post backs to the page, the token value from
    //the cookie should be validated against the token in the view state
    //form field. Additionally user name should be compared to the
    //authenticated users name
    else
    {
      //Validate the Anti-XSRF token
      if ((string)ViewState[AntiXsrfTokenKey] != _antiXsrfTokenValue
          || (string)ViewState[AntiXsrfUserNameKey] !=
               (Context.User.Identity.Name ?? String.Empty))
      {
        throw new InvalidOperationException("Validation of " +
                            "Anti-XSRF token failed.");
      }
    }
  }
}

VB.NET

 Private Const AntiXsrfTokenKey As String = "__AntiXsrfToken"
    Private Const AntiXsrfUserNameKey As String = "__AntiXsrfUserName"
    Private _antiXsrfTokenValue As String

    Protected Sub Page_Init(sender As Object, e As EventArgs) Handles Me.Init
        ' The code below helps to protect against XSRF attacks
        Dim requestCookie = Request.Cookies(AntiXsrfTokenKey)
        Dim requestCookieGuidValue As Guid
        If requestCookie IsNot Nothing AndAlso Guid.TryParse(requestCookie.Value, requestCookieGuidValue) Then
            ' Use the Anti-XSRF token from the cookie
            _antiXsrfTokenValue = requestCookie.Value
            Page.ViewStateUserKey = _antiXsrfTokenValue
        Else
            ' Generate a new Anti-XSRF token and save to the cookie
            _antiXsrfTokenValue = Guid.NewGuid().ToString("N")
            Page.ViewStateUserKey = _antiXsrfTokenValue

            Dim responseCookie = New HttpCookie(AntiXsrfTokenKey)
            responseCookie.HttpOnly = True
            responseCookie.Value = _antiXsrfTokenValue
            If FormsAuthentication.RequireSSL AndAlso Request.IsSecureConnection Then
                responseCookie.Secure = True
            End If
            Response.Cookies.Set(responseCookie)
        End If
        AddHandler Page.PreLoad, AddressOf master_Page_PreLoad
    End Sub

    Protected Sub master_Page_PreLoad(sender As Object, e As EventArgs)
        If Not IsPostBack Then
            ' Set Anti-XSRF token
            ViewState(AntiXsrfTokenKey) = Page.ViewStateUserKey
            ViewState(AntiXsrfUserNameKey) = If(Context.User.Identity.Name, [String].Empty)
        Else
            ' Validate the Anti-XSRF token
            If DirectCast(ViewState(AntiXsrfTokenKey), String) <> _antiXsrfTokenValue OrElse DirectCast(ViewState(AntiXsrfUserNameKey), String) <> (If(Context.User.Identity.Name, [String].Empty)) Then
                Throw New InvalidOperationException("Validation of Anti-XSRF token failed.")
            End If
        End If
    End Sub

2.logout的时候清除相关cookie(这里很重要，否则没有效果)

        Session.Abandon()
        'delete the session and antixsrfToken cookies
        Dim sessionCookie = Response.Cookies("ASP.NET_SessionId")
        Dim antiCookie = Response.Cookies("__AntiXsrfToken")
        sessionCookie.Expires = DateTime.Now.AddHours(-)
        antiCookie.Expires = DateTime.Now.AddHours(-)
        Response.Cookies.Add(sessionCookie)
        Response.Cookies.Add(antiCookie)
        Response.Redirect("./login.aspx", False)