The security of our customers and their applications is of the highest importance to Microsoft. As you may know, we have a process called the Security Development Lifecycle. You can click here to learn more about it. As part of that internal process, we recently discovered an issue with the Windows Azure Software Development Kit (SDK).  As soon as it was discovered, our teams worked quickly to fix it and release a refresh of the SDK. This blog post provides guidance on this issue.

Overview

This refresh of the Windows Azure November 2010 SDK (SDK 1.3) resolves an issue that affects applications developed using SDK v1.3.  We are encouraging affected customers to install the refresh of the SDK and redeploy their application(s).

Who is affected?

This issue affects applications developed using ASP.NET and using the new "Full IIS" feature of SDK v1.3 that have a Web Role deployed. "Web Role" is defined as a single HTTP endpoint and a single HTTPS endpoint for external clients. This is not to be confused with the "Worker Role," which is defined as up to five external endpoints using HTTP, HTTPS or TCP. Each external endpoint defined for a role must listen on a unique port.

In particular, this affects web sites and services that use cookies to maintain state information either within a session or between sessions (if interactions in one session can affect what happens in a subsequent session). These cookies are cryptographically protected so that clients can see that there is state information being passed but cannot see the contents of that state information and cannot change it. In the case of vulnerable Web Roles, it may be possible for clients to determine the contents of the state information (though the client could still not change it). If the web site depended on the client not being able to see the contents, its security could be compromised.

Applying the fix

To apply the fix:

1.     Download and install the refresh of the November 2010 Tools and SDK (recommended).

2.     To upgrade just the SDK, use this link (64 bit) or this link (32 bit)

After you've applied the fix, you'll have to re-package your service and then upgrade or re-deploy your service in the cloud.

Verifying the fix

To verify the fix has been applied:

1.     Check the version number of 'Windows Azure SDK' after upgrading to this refresh, as displayed under 'Programs and Features.' It should be 1.3.20121.1237.

For technical support or to participate in our technical forums, please visit http://www.microsoft.com/windowsazure/support/