decrypt viewstate with key config or web. 5 or above In order to prevent manipulation attacks, . to do this, set the machinekey validation type to aes. Key: derived by a function to perform the encryption and decryption. See full list on alphabot. net2. A new encryption key is generated for an app pool life cycle. . To do this, set the machineKey validation type to AES. x and 2. NET 4 release, you could replace the symmetric encryption and message authentication algorithms used by the cryptographic pipeline within ASP. By default, the 2 keys use auto generated string as key to validate and decrypt ViewState. config. The __VIEWSTATE parameter is not encrypted. Actually the problem is with the viewstate. By default, view state data is stored on the page in a hidden field and is encoded using base64 encoding. There are two different ways in which you can prevent someone from decrypting the ViewState data. ViewState is a form of store where it is capable of storing any serializable objects. This code will generate new keys that you can place in your web. You can see the necessary code to decode viewstate in this article, or see an online demo here. 2 specifications published in 2013 requires the ViewState encryption activation by default. By default, the . config from the chosen project and contains two security issues. NET ViewState deserialization using Blacklist3r and YSoSerial. Let’s decode base64: Pic. 5 Service Pack 1 are not affected by the file content disclosure portion of this vulnerability. Fixing invalid viewstate bug. Invalid length for a Base-64 char array. If your ViewState is to be encrypted, then you require an encryption algorithm & key. The MachineKey is used to encrypt and secure the page’s ViewState. If every server in your farm has the same validation and decryption key, they all know how to read and interpret ViewState generated by any other server in the farm. config file in order to encode and decode the viewstate with the same key instead of one generated on each machine individually. microsoft. Event message: Viewstate verification failed Description. This is the preferred method. ViewState is a Server Side class object which though stores the data on Client Side but it is in Encrypted Form (Hashed format) and hence cannot be read by Plain JavaScript. Therefore, to decrypt the data, Vault must decrypt the encryption key which requires the master key. With the ASP. Data In Transit. web> tag. config must specify the same key used for encrypting the view state. The encryption key is exchanged separately, for example via the Diffie-Hellman (DH) key exchange protocol. You would have to decode and decrypt the ViewState, change something, encrypt and encode the data and then reset the ViewState There's obviously some way to decrypt and encrypt the viewstate clientside or else the client wouldn't be able to communicate with the server, but I haven't figured out how just yet. For example, use YSoSerial. Validation of viewstate MAC failed. config. This happens when encryption key used for encrypting viewstate does not match on different servers in the web farm. 0. The problem comes when a client (browser) sends the request with a viewstate encrypted with the key generated by another worker process. NET framework uses by default to p reserve page and control values between web pages. So here is how the ViewState works: By default, ViewState is serialized into a Base-64 encoded string. Figure 1 is the web. So here is how the ViewState Works, By default, ViewState is serialized into a base-64 encoded string. NET Web page to persist changes to the state of a Web Form across postbacks. Validation of viewstate MAC failed. This is possible because all Exchange servers use the same static key to encrypt/decrypt ViewState. For more information about protecting ViewState, see How To: Configure the Machine Key in ASP. com When you record web tests, please assign the validation key and decrypt key to explicitly specified values. Encryption scrambles the content of a file so only authorized people can read it. To demonstrate this attack, a proof of concept will be performed for a public GitHub project that contained this vulnerability. MAC value is generated using encryption key. Stan has the option to save the encryption key in a safe location. txt file in ECB and CBC mode with 128, 192,256 bit. AES encryption and decryption online tool for free. View State is turned on by default and normally serializes the data in every control on the page regardless of whether it is actually used during a post-back. NET Framework 3. Net. config or web. config file. config you could then use this to decrypt manually if necessary. Verify that you are not running into issues that have been fixed The encryption key as well as the algorithms may be specified. Lookgin at the Webconfig default params page , you can see that the defaults for encryption algorithm is DES, encryption mode is ECB, and the padding scheme is PKCS5. #Encryption. decrypt and tamper with the data encrypted by the server. The master key isn’t stored anywhere. Obtaining a MachineKey using Blacklist3r. Microsoft . We’ll take a quick look at how the performance can differ when we’re using ViewState and when we’re disabling the ViewState in a SharePoint project. The biggest risk is now your key is hard-coded in a file, so you need to make sure your server is secure so that people don’t get that key (otherwise they could hack your viewstate). The first step is to identify the ViewState attribute. Though it is not difficult to decode is and read the view state information. The viewstate is actually decrypted in the server using a secret Machine key which resides on the server. The validation Key is used to validate ViewState and ensure it hasn't been tampered with, and generate unique application-specific session IDs for out-of-process session storage. Using a pre-master secret key to decrypt SSL in Wireshark is the recommended method. It is a Page-Level State Management technique. Because the attacker cannot guess the contents of the <machineKey> element, the attacker cannot provide a valid MAC if the attacker tries to tamper with the __VIEWSTATE payload. Email encryption: Message is encrypted using a private key encryption algorithm and then signed using a public key encryption algorithm. Encryption must have a private key, but we did not specify this private key, because ASP. NET view state and shows with an example how view state works in ASP. which makes it possible to encrypt/decrypt gigabytes of data without. Then submit and get a ping. Thus the ViewState variable is accessed inside JavaScript code with the help of Server Simple encrypting and decrypting data in C#. If you only need it for your web site, you can add it to your web site's web. This article describes ASP. NET request processing. faces. credit cards, soc sec #, etc. ViewState Here AES encryption used with CBC mode used to encrypt and decrypt the data. This was enabled as the default for the 5. When it restarts, it creates a new encryption key (this is the default behavior), which then of course can't be used to decrypt anything encrypted by the previous key (like ViewState). string username = Cryptography. If the encryption key is not specified in web. This ViewState play a key role in handling post back events. Session IDs; Data columns (not Remarks. The ViewStateEncryptionMode property cannot be set in code. Blacklist3r is used to identify the use of pre-shared (pre-published) keys in the application for encryption and decryption of forms authentication cookie, ViewState, etc. Anyhow, lets go back to the topic on how to encrypt the ViewState in ASP. Hence ViewState encrypted and tamper proofed on one machine cannot be decrypted and integrity checked on another machine in web farm. 1. If this application is hosted by a Web Farm or cluster, ensure that configuration specifies the same validationKey and validation algorithm. Invalid Viewstate, Invalid length for a Base-64 char array or string. Using RSA to encrypt large data files in C#. For some reason asp. On PostBack, the ViewState information is loaded and reapplied to the persisted state of the Control in the Control Hierarchy. config or web. It should also be noted that JSF 2. The initialization vector is XORed against the first plaintext block before encryption in CBC mode, as shown in the Wikipedia article on block cipher modes. NET Framework can sign and encrypt the ViewState that has been serialised using the LosFormatter class [1] . Prior to . This encryption prevents tempering of session data on the server. You can use the keys that you create in this article for the validationKey and decryptionKey attributes of the <machineKey> section in the <system. NET to encrypt the ViewState value using the Advanced Encryption Standard. That’s something of a problem. Net. You can also set a stronger level of ViewState to prevent the above decoder from working by changing your encryption key settings in either machine. There this key value will be different across the servers. Exception occurs, because we now are trying to decrypt ViewState with a key that wasn't present when the ViewState was originally generated. Unsealing is the process of reconstructing this master key. web> element in the web. Now, I don't really understand all of this stuff (my boss just said: Heres the problem, fix it). Similarly, if you want a MAC to be created as a hash of your ViewState you need a hashing algorithm & key. View State is the method to preserve the Value of the Page and Controls between round trips. config. Generate a payload with ysoserial that will ping my host, and the known good ViewState with that in the script. Web. This entry was posted in Microsoft and tagged ensure that configuration specifies the same validationKey and validation algorithm, Exception Details: System. Burp decoder. In this article we will see how to decode and view the contents of a viewstate. NET to not use Auto-Generated Key but rather a predefined key. When we deploy an asp. ViewState is a Base64 encoded string and is not readable by the human eye. Use Blacklist3r to identify usage of pre-shared machine key with the following Assuming you've turned the encryption on, which is not the default, ASP. Initialization Vector (IV): a block of bits (a salt value) required to allow a stream to be executed to produce a unique stream independent from other streams produced by the same encryption key; Preparation; Decide what to encrypt and decrypt. Net viewstate decoder / encoder + for free. 1. Decrypt. It can only be set in the @ Page directive or in the < element of the configuration file. Go to this address and get a random machine key. The <machineKey> element is also used by the default Membership provider to hash/encrypt passwords, and is required when deploying your application to a web farm. config (or Web. Key Vault. ViewState, tries to find a colon in it and then extracts the part before the colon and after the colon (idInLogicalMap and idInActualMap); ASP. 2 and later versions it was not for the 2. . The vulnerability was given CVE number CVE-2020-0688. If this application is hosted by a web farm or cluster, ensure that Fixing invalid viewstate bug. config must specify the same key used for encrypting the view state. Figure 4- The administrator is encouraged to save a copy of the encryption key. The viewstate parameter is not encrypted for one or more pages. As you can set the machine keys (for validation and decryption) to a known value in web. There are 2 ways to encrypt data. When the HTML for the page is rendered, the current state of the page and values that need to be retained during postback are serialized into base64-encoded strings and output in the ViewState hidden field or fields. Data is also encrypted since Outsytems ViewState is encrypted. Event message: Viewstate verification failed. Net and the . Download ASP . 0. NET application. MAC value is generated using encryption key. NET has a lot of things related to encryption, such as ViewState, such as Forms Authentication Ticket, which are to be transmitted to the client to ensure its security. config and set it to Always Grab the value of the ViewState generator (__VIEWSTATEGENERATOR) Use the collected values, together with the known static encryption key, to create a payload exploiting the insecure deserialization in ViewState. 5 or above In order to prevent manipulation attacks, . When a post back occurs, the page de-serializes the ViewState and recreates all controls. Now create a page and add a hiddencontrol, Validation key, validation algorithm, decryption key, and decryption algorithm in . The <machineKey> property in web. g. This happens when encryption key used for encrypting viewstate does not match on different servers in the web farm. ViewState for a page is stored as key-value pairs using the System. Instead of creating a complicated function, we will use a tool to generate random machine keys. This key sets up a validation key and a decryption key that is used for generating the MAC that becomes the tool for verifying the validity of state variables. Net viewstate data. Web. . Reason: The viewstate supplied failed integrity check. To reduce the chance of someone intercepting the information stored in the ViewState, it is good design to encrypt the ViewState. There are two different ways in which you can prevent someone from decrypting ViewState data. Stan can now choose “Enable Encryption” from the ribbon which informs him that an encryption key will be created (Figure 4). I'm only assuming the Telerik viewstate can be encrypted because what I've read seems to imply that, but I haven't found a clear example so I'm not sure. Net. The output can be base64 or Hex encoded. This was the non-protected non-encrypted viewstate from step #4. If so, then yes, you can decrypt it (you'll have to write code that will do it). If this application is hosted by a Web Farm or cluster. Net Framework autogenerates a MachineKey. Assuming you've turned the encryption on, which is not the default, ASP. NET Framework versions prior to Microsoft . As such, while you can decypher the viewstate settings using the above program, you can't actually change them and repost to the server. To decrypt the viewstate, you need to find out the encryption algorithm, the encryption mode, padding scheme and what kind of authentication encryption is being used. ASP. Burp Decoder is a simple tool for transforming encoded data into its canonical form, or for transforming raw data into various encoded and hashed forms. Open any page in a browser, go to the source page, copy the view state value in the clipboard. The patch This article describes how to create keys to use for encryption, decryption, and validation of Forms authentication cookie data. AES supports 128, 192, and 256-bit encryption, which can be determined by the key size, 128-bit encryption key size is 16 bytes, the 192-bit encryption key is 24 bytes and 256-bit encryption key size is 32 bytes. If those keys are changed, then the encrypted ViewState during you record web test wouldn't be able to validate and decrypt. config . After the first block is decrypted, you still have an intermediate value which has been XORed with the plaintext — without this, you have little hope of recovering the plaintext. However, the truth is, if the encryption and the data integrity check (MAC) are disabled, accessing the content is much simplier than it seems. NET Framework version 4. 6. NET framework uses that machine’s own MachineKey, but should your view state get sent to another content delivery server with a different key, well, then the ViewState will be invalid. ASP. In this kind of algorithms, the key to encrypt and decrypt data is the same. 0 any encryption/decryption using machine key; All the above Validation of viewstate MAC failed. Decode simply reverses the process. (the default Rijndael key length is. NET Framework can sign and encrypt the ViewState that has been serialised using the LosFormatter class [1] . The Machine Key <machineKey> element helps to control tamper proofing and encryption of ViewState, forms authentication tickets, and role cookies. The true meaning of javax. Initialization Vector (IV): a block of bits (a salt value) required to allow a stream to be executed to produce a unique stream independent from other streams produced by the same encryption key; Preparation; Decide what to encrypt and decrypt. View 1 Replies VS 2010 Viewstate For Tab Container Jun 29, 2011 Introduction: Yahoo! bug bounty program is still young and I believe that they have been pushed to do this when they were not ready for it! Many of their web pages had not even been scanned by an automatic commercial scanner when they started running their bounty program and they will definitely lose profit on that. Viewstate is not encrypted by default, it is only encoded, so you want to decode it, not decrypt it. The machine key is a Symmetric encryption key, since each machine must be able to encrypt and decrypt data. net web application into a web farm environment, each web servers machine. The two servers use different keys to encrypt the viewstate information. config file configures algorithms and keys to use for encryption, decryption, and validation of forms-authentication data and view-state data, and for out-of-process session state identification. A new encryption key is generated for an app pool life cycle. SecureRandom to generate truly random tokens and use SSL to make it more difficult to intercept the request. If this application is hosted by a Web Farm or cluster, ensure that <machineKey> configuration specifies the same validationKey and validation algorithm. if you dont have them, then when a new session starts, it generates them and stores them in RAM which the other servers in the farm cant obviously read and therefore dont know the codes to decrypt the viewstate. When the application is hosted on a single machine, there is no issue as the key will always be same for both encryption and decryption. The interesting thing is the key gets regenerated after a certain time. But this will not be the case in web farm. NET encrypts the viewstate using an Autogenerated Key when the process spins up. How to Exploit Microsoft SharePoint for SSI and ViewState Deserialization. For example if you have TextBox control on the page and user modified the text and you want to handle the text changed event. This code takes a look the the request parameters, takes the one with the name javax. For this you must manually generate the two cryptographically random key values and copy the keys to each Machine. The ViewStateUserKey property is an optional addition to the data used in ViewState MAC calculation. config level via the ViewStateEncryptionMode attribute. View State is turned on by default and normally serializes the data in every control on the page regardless of whether it is actually used during a post-back. NET ViewState Decoder. This will execute a "Post" as requested method and will send the data in the body of the request. Moral: Don't change ViewStateUserKey when there is pending ViewState that hasn't been posted back and cracked open yet. vault operator unseal [PASTE Machine Key contains a set of fields like validation key, decryption key and so on where unique keys are to be entered. com Viewstate encryption is a best practice and a good way to provide an additional level of security (a defence in depth approach). This instructs ASP. Yet, here is a very good, in-depth article on ViewState that doesn't even mention it! Then there's this W3Schools article on ViewState that seems to indicate that posted form values are maintained via ViewState, but that's not true. When we deploy an asp. In a load balanced environments where there are multiple servers there was a need to set the machine key in the machine. See also: Wireshark Alternatives for packet sniffing. Can you modify an encrypted ViewState if you have the encryption key? If enableViewStateMac is off, then it is theoretically possible. UI. AutoGenerate cannot be used in a cluster For the sake of completeness, I ought to mention that you should encrypt your random token using a good encryption algorithm such as a 256-bit BASE64 hash, use java. <app Settings <add key="CMSUseViewStateUserKey" value="false"/> Encryption Keys web. It should look like this: Actually, if all you want to do is prevent tampering, you don't need to encrypt the viewstate; adding a secure hash is enough. The ViewState for the controls in a page is stored as Base64 encoded strings in name - value pairs. 0 so that it can decrypt version 3. NET world, you could modify the machine. config) file across your Web farm. On postback, the ViewState information is loaded and reapplied to the persisted state of the control in the control hierarchy. The entry for Machine Key looks something like this. You can optionally encrypt viewstate, although it does impact performance, as described in the article. If they match, the message is intact and if they don't then the receiver knows that someone has been messing with it. When you didn't set this, you would get similar exceptions as the ones mentions above. NET view state is the technique used by an ASP. Database encryption: Usually leverages private key encryption to facilitate column level encryption. NET. Values set in the @ Page directive override any values set in the configuration file. There are It stores text from txtSource texbox into ViewState with key, Encrypt and Decrypt function in SSRS. NET ViewState strings and display in treeview format This tool allows you to generate random keys for validation and encryption/decryption of the ViewState in your ASP. The most secure way is using the Session but, of course, you will have to manage the session size. 1. NET will use the web site machine key as the key used to encrypt and sign ViewState and cookies. The problem comes when a client (browser) sends the request with a viewstate encrypted with the key generated by another worker process. N That is the encryption codes and methods IIS uses to encrypt and decrypt the viewstate. The first one is known as symmetric encryption. Kind regards, Miguel Figure 3- Data Encryption Management page. The role of these keys as mentioned earlier is to manage the encryption for application services like cookies, viewstate etc. Net with C# and VB. Key: derived by a function to perform the encryption and decryption. config you could then use this to decrypt manually if necessary. to reduce the chance of someone intercepting the information stored in the viewstate, it is good design to encrypt the viewstate. ). config file on multiple machines to synchronise the machine keys used to validate viewstate etc. -f, --decryptDataFilePath file path where the decrypted information stored -p, --purpose purpose -m, --modifier Modifier used to encode the viewstate -s, --macdecode Used to decide whether viewstate is MAC enabled or not -l, --legacy Used to decide whether viewstate legacy decrypt -o, --outputFile Output file path -i, --IISDirPath Application See full list on valencynetworks. You can also change the Method of the "Link / Button" to Submit. config. The <machineKey> Element configures keys to use for encryption and decryption of forms authentication cookie data and viewstate data, and for verification of out-of-process session state identification. Adding ACL for access to the RSA Key container. – tdammers Aug 4 '11 at 20:48 The encryption key is also stored with the data, but encrypted with another encryption key known as the master key. However, in May 2016 the Mojarra developers started backporting default client-side ViewState encryption to 2. com Troy Hunt has a magnificent blog post describing how ViewState MAC works if you are interested in the details. com So the hashcode is determining if the viewstate information was modified or tampered with and adding the encryption will prevent users from viewing and reversing the base64 to read the content? Assuming you're not using SSL, my guess is encrypt only when the information is valuable (e. ViewState is the method that the ASP. Therefore each TLS connection exchanges its own ephemeral and unrecoverable session key (independent of the used server certificate), and a stolen private key is of no help to an adversary trying to decrypting the communication. File encryption: Implemented using encryption software which can be public or private keys. NET view state and shows with an example how view state works in ASP. See full list on docs. In case of dynamically generated encryption key, when user submits the page to the server, after the app pool has been recycled. In the old . AES Encryption offers good performance and a good level of For example, one of the key features that is important to understand about ViewState is how it tracks dirtiness. config . this instructs asp to encrypt the viewstate value using the advanced encryption standard. 1. It is an aes calculator that performs aes encryption and decryption of image, text and . HttpException: Validation of viewstate MAC failed, generate aes machine key, If this application is hosted by a Web Farm or cluster, program to generate machine keys iis windows, step View State Key Generator: When either hosting several applications on one instance of IIS or hosting applications on a farm you will most likely encounter View State issues/conflicts. Form Authentication uses this key to encrypt/decrypt the form authentication tickets. Is there some sort of decryption key provided when I log into the site? In brief, ViewState is a Base64 encoded string and is not readable by the human eye. NET. The machine key in IIS is set for auto-generation. Solution. As the viewstate data is encrypted and decrypted, unique key is used to encrypt/decrypt this data. Pawan Jaiswal in The Startup. Session IDs; Data columns (not "The viewstate is invalid for this page and might be corrupted" This article describes some techniques that can be used for debugging and for resolving problems with view state. We have been getting some questions regarding viewstate-related errors like "The viewstate is invalid for this page and might be corrupted" There are several ways to get around this problem: 3) Configure ASP. 0. Build a script that can encrypt the known good ViewState and submit it. You can run into problems if the key change s The MachineKey defines a validation method, validationKey and decryptionKey which are used in the encryption/decryption algorithm. 1 release, but is a recommended practice for all versions, to make this change add the viewStateEncryptionMode attribute to the pages node in web. This is used mainly at two places. NET will use the web site machine key as the key used to encrypt and sign ViewState and cookies. x and 2. The sender get the message, hashes it using the same private key as the sender (this is important as just the one key is involved on both sides), then compares the resultant MAC with the one sent alongside the original message. Do not use it if your ViewState does not contain sensitive data because encryption significantly adds to the size of the ViewState and this impacts performance. Attackers can specify arbitrary […] Continue reading Here Mudassar Ahmed Khan has explained with an example, how to use ViewState variable inside JavaScript in ASP. x branches. All). MachineKey. Decrypt the ViewState variable to show my encryption key works. faces. ViewState Encryption protects the ViewState confidentially by encrypting the ViewState value. config so that the conflict… This article describes ASP. I’d typically suggest both (MachineKeyProtection. config file inside the <system. NET 2. Maybe it is time to specify a machine key just paste this into your web. See full list on devblogs. As the ViewState data is encrypted and decrypted, a unique key is used to encrypt/decrypt this data. viewstate is a decoder and encoder for ASP . It is a Page-Level State Management technique. By default, the ViewState MAC is enabled, and ViewState Encryption is not. net web application into a web farm environment, each web servers machine. net renders the hidden viewstate field at the top of the page and then renders the viewstateencrypted hidden field at the bottom of the page. In this blog post, Sanjay talks of various test cases to exploit ASP. This section can be declared at the machine, site, and application levels, but not at the subdirectory level. 1. NET 2. Test what happens when a bad ViewState is submitted. The server that receives the postback request tries to decrypt the viewstate with its key which is different from the key it as encrypted. 0 and version 4. 0 the way you would do this is via the machineKey element validation attribute. NET. When the application is hosted on a single machine, then there is no issue as the key will always be same for both encryption and decryption process. NET Framework version 4. By default, ASP. Taking a look: ViewState. Send the malicious ViewState to the server; The video below demonstrates the exploit. The key that is used to calculate the MAC is specified in the application's element in the Web. config file or Machine. If the encryption key is not specified in web. In case of dynamically generated encryption key, when user submits the page to the server, after the app pool has been recycled. x when they realized that unencrypted ViewStates lead to RCE vulnerabilities. some general errors you may face , when you earn dedicated server with windows server and host your website applications on IIS service is Another thing that can happen is if you have view state encryption turned on (which is by default) these errors can sometime result from posting back a page before it is fully rendered. microsoft. When Wireshark is set up properly, it can decrypt SSL and restore your ability to view the raw data. . The returned string can then be used to pass back to the client as a cookie value or a query string value without concern for viewing or tampering. NET encrypts the viewstate using an Autogenerated Key when the process spins up. However it is also not difficult to decode the viewstate and view the contents of the viewstate when it is passed over the wire. As shown in the figure below, ViewState MAC is enabled and Encryption is disabled which means it is not possible to tamper ViewState without MachineKey (Validationkey). failed . Scenarios and Troubleshootings. Using a pre-master secret key to decrypt SSL and TLS. Whilst client-side ViewState encryption is the default in Mojarra 2. Archived Forums > SQL Server Reporting Services, Power View. Normally, Asp. Now that the decryption key has been made publicly available, this allowed TeslaCrypt expert BloodDolly to update TeslaDecoder to version 1. By default, ASP. The decryption Key is used for encryption and decryption of authentication tickets and encrypted ViewState information. AutoGenerate cannot be used in a cluster. NET automatically generated. In . To fix this issue, you have to use the same key across all servers in your webfarm. NET 2. If there are multiple sites/applications that need to use the same machineKey for encrypting/decrypting, that is when you would use a machine-scoped configuration file. It supports the different viewstate data formats and can extract viewstate data direct from web pages. Developers tend to believe that if ViewState is a serialized structure, moreover, a base64-encrypted one, no attacker will be able to get to its contents. Encryption has the added benefit of hiding the viewstate information entirely though. Decode the ASP. Validation key, validation algorithm, decryption key, and decryption algorithm in . View State is the method to preserve the Value of the Page and Controls between round trips. The Advanced Encryption Standard or AES is also called Rijndael cipher. Otherwise they will be automatically generated by MyFaces . security. This means you need a secure way to transmit the key to other people. Firstly, the validation and decryption key are hard coded and secondly, the ViewState encryption mode has been disabled. The RSA key container was not found. The second parameter is an enum that indicates if you want encryption, validation or both. As you can set the machine keys (for validation and decryption) to a known value in web. Improved Encryption Pipeline. In order for us to really understand what impact the ViewState can have on the page rendering process, we’ll dig into the details of the what the ViewState looks like. 0 onwards Microsoft provided us with an option to specify ViewState encryption in the page level or web. 0 of Validation of viewstate MAC failed. StateBag object. decrypt viewstate with key