Windows 7 Ultimate and Enterprise editions ship with AppLocker, which is a Group Policy based application control solution. AppLocker is a big improvement over Software Restriction Policies, as it provides a more flexible and intuitive solution to its predecessor. Here we discuss the pros and cons of Windows AppLocker.
Deploying Application Control Policies through AppLocker
AppLocker can ensure that users are only allowed to run authorized executables, installer packages and scripts. It provides a good selection of rules, including filename, publisher and file hash. In addition, it is possible to identify applications based on their file properties, such as product name and version, although this capability is restricted to signed applications.
The lack of support for management consoles and control panel applets, introduces a slight security concern, as unauthorized snap-ins and applets may be launched by the user. Other areas of Group Policy can be configured to hide control panel applets, but this does not stop a rogue control panel applet from actually running. Management console snap-ins can also be controlled through Group Policy settings, and although this does go further than superficial hiding of snap-ins, the whitelisting of third party snap-ins could prove challenging, so it’s a shame that AppLocker can’t control snap-ins through the restriction of msc files.
Although AppLocker can handle software installation packages, a high proportion of software installers will require local admin rights to install. Granting local admin rights to a user will make any attempt to control application execution a futile undertaking, as the user will effectively have complete control over their desktop, and so the whitelisting of software packages with AppLocker is severely limited.
End User Experience
Where AppLocker really disappoints is in its end user experience. The end user message that is displayed when an application is blocked can’t be configured, and so the IT department are not able to convey a meaningful message to their user base when an application is blocked. This is further compounded by the lack of any method for a user to request access to an unauthorized application. It’s highly unlikely that the IT department will get application control policies configured correctly first time, and so the lack of informative messaging and a user feedback mechanism will make the ongoing fine tuning and maintenance of policies more challenging.
The application of AppLocker to more advanced users, such as technical users or laptop users, could prove problematic, as applications can only be blocked, which may prove too restrictive and lead to productivity issues. The ability to warn and audit, as opposed to blocking, would have made it possible to apply AppLocker policies to a much broader range of users, but this capability is sadly lacking.
As with most of Microsoft’s built-in system management tools, AppLocker provides no reporting capabilities, which could make it difficult to fully assess the impact of the applied policies.
Conclusions
There is no doubting that AppLocker is a big improvement over Software Restriction Policies, but it still falls short in a number of areas, which may restrict its adoption for application control to smaller implementations of task based workers, where users require little flexibility in their job role. As a user’s requirements become more complex, AppLocker could prove difficult to apply without severely compromising an end user’s productivity and creating a burden on the IT department to constantly update policies.
