Is it possible to decode EventValidation and ViewState in ASP.NET?

Question

如何解码 ASP.NET EventValidation 和 ViewState？

Answer 1

I answered a similar question recently, Getting values from viewstate using JQuery? .

Basically, by default ViewState is just Base64-encoded, so you can decode it as long as the administrator hasn't configured the site to encrypt it. Quoting from my previous answer:

If you are writing the control for your own consumption and you only need to read from ViewState , you could do so, but I wouldn't recommend it unless you find a well-debugged library to parse it for you. The format is a bit hairy (see ViewState: All You Wanted to Know for more details ).

That link provides an extremely thorough and clear introduction to ViewState .

As for Event Validation, I'm unsure whether it's Base64-encoded or if it just looks like Base64 (I can't find a conclusive, authoritative reference). This Rexiology article might help though.

Answer 2

我不确定 EventValidation，但您可以使用 Fritz Onion 的ViewState Decoder 解码 ViewState 。

Answer 3

我最近需要解码 ViewStates，发现这个工具很有用： View Statedecoder

Answer 4

Create a simple windows app and use Convert.FromBase64(str) to decode ViewState data if it is not encrypted.

Note: GridView causes encryption.

Answer 5

You can use this link if use python.

Best way is use this link .

A small Python 3.5+ library for decoding ASP.NET viewstate.

First install that: pip install viewstate

>>> from viewstate import ViewState
>>> base64_encoded_viewstate = '/wEPBQVhYmNkZQ9nAgE='
>>> vs = ViewState(base64_encoded_viewstate)
>>> vs.decode()
('abcde', (True, 1))