Is there a change between how session/cached info is stored with dif. Azure Guest OS?

Question

I have an application running perfectly on windows azure since april.

Unfortunetly, about 2 weeks ago it suddenly stopped. It would not run again until we upgraded the Azure Guest OS to the newest Version(1.7).

Over the last two weeks we're noticing that session data transferred between pages (eg. http://program-url/cars/edit/3 will be missing the 3, etc...

IN addition, info stored in sessions will randomly dissapear and reappear, with no apparent reason.

Our application is built on Asp.net MVC 1 with Entity Framework 3.5. Our Db stuff is hosted on SQL Azure.

Does anyone know of a reason why this would be happening, or how to fix it?

Answer 1

I don't peronsally know a reason, but you should check the Guest VM OS release notes, which provide all the security patches that are included in a release. Chances are one of the patches changed ASP.NET behavior in some way that is impacting you.

MSDN: Azure Guest OS Releases http://msdn.microsoft.com/en-us/library/ee924680.aspx

MSDN: Azure Guest OS 1.7 http://msdn.microsoft.com/en-us/library/gg248099.aspx

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(The rest of this is just a guess, but figured I'd share)

OS Release 1.7 does include MS Bulletin MS10-070 which patched up a security hole in ASP.NET where the error pages could allow threats to access protected information (Vulnerability 2418042).

This particular patch caused us some problems on our non-Azure systems, as it modifies the way machine key encryption is used when ASP.NEt shares information. Depending on your caching, this may be the cause.