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ASP.NET Vulnerability

Ronan_ · 2010-09-21 22:48:48

This might interest some of you.. Vulnerability affecting all versions of ASP.NET discovered This could allow an attacker to read Viewstate or download any file from a server e.g. web.config Make sure CustomErrors is set on, and that all errors are being sent to one generic error page. This page should return as little…

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21-09-2010 11:48pm

#1

Ronan_

Closed Accounts Posts: 48 ✭

Join Date: September 2008

Posts: 45

This might interest some of you..
Vulnerability affecting all versions of ASP.NET discovered

To understand how this vulnerability works, you need to know about cryptographic oracles. An oracle in the context of cryptography is a system which provides hints as you ask it questions. In this case, there is a vulnerability in ASP.NET which acts as a padding oracle. This allows an attacker to send cipher text to the web server and learn if it was decrypted properly by examining which error code was returned by the web server. By making many such requests (and watching what errors are returned) the attacker can learn enough to successfully decrypt the rest of the cipher text.

This could allow an attacker to read Viewstate or download any file from a server e.g. web.config

Make sure CustomErrors is set on, and that all errors are being sent to one generic error page. This page should return as little information as possible to the user.

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