The Windows Azure Team has released a security refresh for the v1.3 SDK aimed to fix the issue where by the client to determine the content of the state information passed by the web role.
If you have downloaded the V1.3 SDK prior to 3 Feb 2011, perform the quick check to see if you need to have it patched.
Control Panel > Programs > Programs and Features
Scroll to Windows Azure SDK and note the version number. Anything less than 1.3.20121.1237 means that your web role(s) may be vulnerable.
Download the patch files from Microsoft (links below), and install in. Zip through the various EULA and install options. You may be prompted to shut down some services for the patch to go through.
Verify that the installation was successful (or you already have a patch SDK)
Full details and patch links available directly from Microsoft: http://blogs.msdn.com/b/windowsazure/archive/2011/02/03/windows-azure-software-development-kit-sdk-refresh-released.aspx