CODEWITHSUNDEEP
windowswindows-7windows-xpuac
carpat
carpat

Reputation: 869

Software updates and UAC

How does Windows handle security and software updates? I need to deploy software to several computers, which will be regularly updated. The update just downloads and runs the new installer. Obviously for the initial installation an administrator needs to run the installer, but after that is the installer white-listed to be run as a non-administrator? This is for XP and 7. The installer is an msi generated with WiX.

Upvotes: 0

Views: 442

Answers (2)

Alexey Ivanov
Alexey Ivanov

Reputation: 11878

No, the installer is not white listed. Even if it were, the update is another installer. So the answer to your question: users will have to confirm elevation in UAC prompt.

Firefox and Opera are the examples. Every time an update is ready to be installed, the updater shows UAC prompt. Chrome on the other hand updates without UAC prompt, simply because it installs into user's profile which is not write-protected (I mean current user has full rights).

Firefox plans to implement a service to facilitate the update process. The service runs under system privileges, it can start the updater with system privileges without user consent for elevation, because it already has full access to the system. This is how antivirus software updates itself. Usually there are two processes: the service and the client which displays UI and communicates to the service.

In the case of MSI, there are system policies. For example, you can enable a policy according to which any Windows Installer-based installation will be run elevated. Usually patches (minor updates) are run elevated. There may exist a policy which controls major updates (where the old version is uninstalled and then a new one is installed), yet I am not aware of such.

Upvotes: 2

ChrisV
ChrisV

Reputation: 3423

I don't know WiX, but it is possible to generate an .msp patch for your existing installer package. If the MSI is properly filled out with an MsiPatchCertificate table, you can avoid elevation when patching.

More details here at MSDN: User Account Control (UAC) Patching, Patching Game Software in Windows XP, Windows Vista, and Windows 7

Upvotes: 1

Related Questions