Summary

Netsparker detected that MAC validation is disabled in ViewState data.

Impact
An attacker can tamper with the application's state variables located in the ViewState data structure.
Actions To Take
  1. For page-based protection, place the following directive at the top of affected page.
    <%@Page EnableViewStateMAC=true %>
    
  2. You can also set this option for the whole application by using web.config files. Apply the following configuration for your application's web.config file.
    <System.Web>
        <pages enableViewStateMac="true">
    </System.Web>
Remediation
ASP.NET uses a hash code-based integrity solution called "ViewStateMac" to protect ViewState parameters against tampering attacks. You can implement this solution on a page or application level.
Classifications
WASC-15