From the Microsoft Dynamics AX Blogs: 2012 security upgrade tool; POS button shortcuts; DLL deployment; HR in Enterprise Portal
Security Upgrade Advisor Tool for Dynamics AX 2012: Parth Pandya from the Microsoft Dynamics AX Server Team says that the security framework has undergone significant changes between Dynamics AX 2009 and 2012. There is no automatic path for upgrade of security configuration from AX 2009 to AX 2012. "In order to assist the upgrade of security settings, we have written a tool called the Security Upgrade Advisor," he says.
Pandya points out the differences between security in AX 2009 and AX 2012, for things like groups and domains in 2009 and security roles in 2012. You can read more about the upgrade approach here.