title: Forms auth: User has been changed during session
body: <p>We are having a strange case. </p>
  
  <p>User "A" logged into our web-system (ASP.NET MVC, Forms Auth), was working for some time, then his user name changed to "B"</p>
  
  <p>IIS Logs:  </p>
  
  <blockquote>
    <p>2011-11-29 05:59:26 GET /PlacementOrder/ - 80 userA@mail.com
    191.114.62.70 Mozilla/4.0+ 200 0 0 2118   2011-11-29 05:59:26 POST /PlacementOrder/Index_GetData - 80 userB@mail.com 191.114.62.70
    Mozilla/4.0+ 200 0 0 551</p>
  </blockquote>
  
  <p>That case is very critical — user can't see data of others.</p>
  
  <p>Does anyone have any ideas? Please! </p>
  
  <p>FINALLY:<br>
  We've decided it is a bug somewhere in ASP.NET, IIS or wherever more. We added extra-checking for IP in Application_AuthenticateRequest and AuthCookie.UserData.</p>
  
  <p>Thank you for helping us! </p>