Windows Vista Security: Praxisorientierte Sicherheit für Profis

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Chapter 4

CHAPTER 4

Installing, Configuring, and Maintaining

Software

4

Most modern software and game programs have automated setup processes, making

it easy to install and run your programs. Resolving problems if automated setup fails

or if a program does not run as expected is not so easy, however, which is why you

need a strong understanding of how software installation works and the techniques

you can use to diagnose and resolve any problems you encounter.

Software Installation: What’s Changed

Compared to earlier releases of Windows, the processes of installing, configuring,

and maintaining software and game programs work differently in Windows Vista.

Primarily, this is because of changes to:

• The way accounts are used

• The way User Account Control (UAC) works

• The removal of the Add/Remove Programs utility

• The way application access tokens are used

• The way applications write to the system locations

Unlike earlier releases of Windows, Windows Vista has only standard user accounts

and administrator accounts. When you log on to Windows Vista, you use one type

of account or the other, removing the gray area between these two types of accounts

that was previously available through the Power Users group. In Windows Vista, the

Power Users group is included only for backward compatibility, and you should use

it only when you need to resolve compatibility issues.

In Windows Vista, software installation, configuration, and maintenance are pro-

cesses that require elevated privileges. Because of this, only administrators can

install, configure, and maintain software. As discussed in Chapter 3, elevation is a

feature of UAC. Because of UAC, Windows Vista is able to detect software installa-

tion. When Windows Vista detects a software-installation-related process, it

prompts for permission or consent prior to allowing you to install, configure, or

maintain software on your computer.

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Chapter 4: Installing, Configuring, and Maintaining Software

Windows Vista does not include an Add/Remove Programs utility. Instead, it relies

completely on the software and game programs themselves to provide the necessary

installation features through a related Setup or Autorun program.

Most programs created for Windows 95, Windows 98, Windows Me,

Windows 2000, and Windows XP use setup.exe programs. Programs

created for Windows Vista and later versions of Windows can use

autorun.exe programs, particularly if those programs use current ver-

sions of Windows installers. For simplicity’s sake, I’ll refer to both

Setup and Autorun programs as Setup programs.

Windows Vista also provides new architecture guidelines for software and game pro-

grams that fundamentally change the way software access tokens are used and the

way software programs write to system locations. These changes are so far-reaching

that software not specifically designed to support the new architecture guidelines is

considered legacy software. This means there are two general categories of software

that you can use with Windows Vista:

• Windows Vista-compliant applications

• Legacy applications

Any software written specifically for Windows Vista’s new architecture guidelines is

considered a compliant application and can be certified as compliant with Microsoft.

Applications certified as compliant have the Windows Vista-compliant logo. Appli-

cations written for Windows Vista have access tokens that describe the privileges

required to run and perform tasks. Windows Vista-compliant applications fall into

two general categories:

Administrator user applications

If an application requires elevated privileges to run and perform tasks, it is con-

sidered an administrator user application. Administrator user applications can

write to system locations of the registry and filesystem.

Standard user applications

If an application does not require elevated privileges to run and perform tasks, it

is considered a standard user application. Standard user applications should

write only to nonsystem locations of the registry and filesystem.

Any application written for an earlier version of Windows is considered a legacy

application. Legacy applications run as standard user applications and in a special

compatibility mode that provides virtualized views of file and registry locations.

When a legacy application attempts to write a system location, Windows Vista gives

the application a private copy of the file or registry value. Any changes are then writ-

ten to the private copy, and this private copy is in turn stored in the user’s profile

data. If the application attempts to read or write to this system location again, it is

given the private copy from the user’s profile.