How do I fix validation viewstate failed MAC?

How do I fix validation viewstate failed MAC?

Validation of viewstate MAC failed. If this application is hosted by a web farm or cluster, ensure that configuration specifies the same validationKey and validation algorithm. AutoGenerate cannot be used in a cluster.

What is the purpose of Enableviewstate MAC in asp net?

The MAC ensures that the client hasn’t tampered with these fields. When EnableViewStateMac is set to true, this code is validated by the server when the client submits the __VIEWSTATE hidden form field during post back. This setting has been enabled (true) by default for all versions of ASP.NET.

Where is EnableViewStateMac setup?

Set the EnableViewStateMac attribute using the @ Page directive in the . aspx file. When the page is requested, the dynamically generated class sets the property. This attribute should never be set to false in a production Web site, even if the application or page does not use view state.

What is machineKey in web config?

What Is Machine Key? The machineKey element in the ASP.NET web. config file specifies the algorithm and keys that ASP.NET will use for encryption. By default the validationKey and the decryptionKey keys are set to AutoGenerate which means the runtime will generate a random key for use.

Where do I put machineKey in web config?

If you have access to the IIS management console for the server where Orchard is installed, it is the easiest way to set-up a machine key. Uncheck “Automatically generate at runtime” for both the validation key and the decryption key. Click “Generate Keys” under “Actions” on the right side of the panel. Click “Apply”.

How do I decode ViewState online?

Use Fiddler and grab the view state in the response and paste it into the bottom left text box then decode.

How do I enable EnableViewStateMac?

2, the runtime enforces EnableViewStateMac=true. If an application sets <%@ Page EnableViewStateMac=”false” %> as a directive or as a config setting, the runtime ignores it and pretends that the developer had written “true” instead. Currently the . NET Framework 4.5.

How is ViewState encoded?

ViewState is base64-encoded. It is not encrypted but it can be encrypted by setting EnableViewStatMAC=”true” & setting the machineKey validation type to 3DES. If you want to NOT maintain the ViewState, include the directive < %@ Page EnableViewState=”false” % > at the top of an .

What is ViewStateEncryptionMode?

The ViewStateEncryptionMode enumeration provides values for specifying whether the view-state information in a Page object is encrypted. The ViewStateEncryptionMode value can be set only in the @ Page directive or in the section of the configuration file.

How do I find the machineKey for web config?

To do this, please follow these instructions:

1. Go to IIS console on one of the webservers > Sites > select the Pyramid website > double-click on Machine Key icon in center pane.
2. In Machine Key dialog, click on Generate Keys and then Apply.
3. Copy the generated validation and decryption keys to the notepad.

How do I set up machineKey?

How do you view ViewState?

Press F12 in keyboard and invoke developer tools in chrome. Then go to the ‘Resources’ tab. Then from the left pane, exapnd ‘Cookies’ and click on the particular website on the list. Then you will see the cookie name along with the value and other details in the right pane.

Why does my Mac validation fail when generating a __VIEWSTATE payload?

The result is that, if one server generates a __VIEWSTATE payload that a different server consumes, the consumer will experience a MAC validation failure. By adding an explicit element to the application’s Web.config file, the developer tells ASP.NET not to use the auto-generated cryptographic key.

What does a Mac validation error look like?

A MAC validation error will resemble the following example: Server Error in ‘/’ Application. Validation of viewstate MAC failed. If this application is hosted by a web farm or cluster, ensure that configuration specifies the same validationKey and validation algorithm. AutoGenerate cannot be used in a cluster.

How does the server check the value of the __VIEWSTATE field?

When the __VIEWSTATE field is consumed, the server checks the current Page’s ViewStateUserKey property and validates it against the value that was used to generate the __VIEWSTATE field. If the values do not match, the request is rejected as potentially malicious.

Why is the __VIEWSTATE field protected by message authentication code?

If an attacker submitted a malicious __VIEWSTATE payload, the attacker could potentially trick the application into performing an action that it otherwise would not have performed. To prevent this kind of tampering attack, the __VIEWSTATE field is protected by a message authentication code (MAC).