Forms Authentication: Remember Me? Its Hard Not Too!

Posted by on April 4, 2012 · Comments Off on Forms Authentication: Remember Me? Its Hard Not Too!
Filed under: Development, Security 

ASP.Net Forms Authentication is a great way to authenticate users for the application.  Microsoft has done a really good job at implementing this to make it simple and straightforward for developers.  Forms Authentication allows for a user to enter their user name / password combination for an application and have that validated against a backend ...

.Net Validators – Don’t Forget Page.IsValid

Posted by on March 31, 2012 · Comments Off on .Net Validators – Don’t Forget Page.IsValid
Filed under: Development, Security 

ASP.net does a good job of providing a simple way to provide input validation.  Just about any security presentation or class will put a lot of emphasis on the concept of input validation.  One of the techniques that you can use with web forms is the built in validator controls.  In general, these controls automatically ...

WCSA – Web.Config Security Analyzer

Posted by on March 31, 2012 · Comments Off on WCSA – Web.Config Security Analyzer
Filed under: Development 

In an ASP.Net application, the web.config file contains a lot of security settings that shouldn’t be overlooked.  There has been no real easy way to review the file without manually looking at each setting or running an expensive tool.  To fill this gap, WCSA was born.  This initial release is relatively simple and by no ...

Request Validation in ASP.Net 4.5 Beta

Posted by on March 11, 2012 · Comments Off on Request Validation in ASP.Net 4.5 Beta
Filed under: Security 

The next version of Microsoft’s ASP.Net framework is currently in Beta and there are some pretty cool changes to how Request Validation works in version 4.5.   Up until now, there were two ways to enable or disable request validation: Globally – This controls request validation for the entire application. ...

ASP.Net: Tampering with Event Validation – Part 2

Posted by on February 10, 2012 · 1 Comment
Filed under: Development, Security, Testing 

In part 1 of this series I demonstrated how to modify the values of a list box and access data I was not given access to by manipulating the view state and event validation parameters.  Remember, the key to this is that ViewStateMac must be disabled.  In this post, I will be demonstrating ...

ASP.Net Webforms CSRF Workflow

Posted by on February 7, 2012 · Comments Off on ASP.Net Webforms CSRF Workflow
Filed under: Security, Testing 

An important aspect of application security is the ability to verify whether or not vulnerabilities exist in the target application.  This task is usually outsourced to a company that specializes in penetration testing or vulnerability assessments.  Even if the task is performed internally, it is important that the testers have as much knowledge about vulnerabilities ...

ASP.Net: Tampering with Event Validation – Part 1

Posted by on February 6, 2012 · Comments Off on ASP.Net: Tampering with Event Validation – Part 1
Filed under: Development, Security 

UPDATED 12/13/2012 - This post was updated to include a video demonstration of tampering with data with Event Validation enabled.  The video is embedded at the bottom of the post. My last post brought up the topic of tampering with Event Validation (__EVENTVALIDATION) and how it is protected with the ViewStateMAC property.  This post, and the ...

ViewStateMAC: Seriously, Enable It!

Posted by on February 1, 2012 · Comments Off on ViewStateMAC: Seriously, Enable It!
Filed under: Development, Security 

I have been doing a lot of research lately around event validation and view state.  I have always been interested in how Event Validation worked under the covers and if it could be tampered with.  I will attempt to explain that it is, in fact, possible to tamper with the Event Validation field in a ...

ASP.Net Insecure Redirect

Posted by on January 9, 2012 · Comments Off on ASP.Net Insecure Redirect
Filed under: Development, Security 

It was recently discovered that there was a vulnerability within the ASP.Net Forms Authentication process that could allow an attacker to force a user to visit a malicious web site upon success authentication.  Until this vulnerability was found, it was thought that the only way to allow the Forms Authentication redirect (managed by the ReturnUrl ...

ASP.Net Forms Authentication Bypass

Posted by on January 5, 2012 · Comments Off on ASP.Net Forms Authentication Bypass
Filed under: Security 

It was recently announced that there is a vulnerability in ASP.Net Forms Authentication.  The vulnerability allows an attacker to assume the identity of another user within the application without the need to know the victim’s password.  This is a critical vulnerability as it could allow users to execute commands they do not have access to.   ...

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