my personal blog about systemcenter

Archive for February, 2018

http://seclists.org/fulldisclosure/2018/Feb/33 , Skype Updater Escalation Prevent through GPO

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There was published a issue with the skype installer

http://seclists.org/fulldisclosure/2018/Feb/33

This can elevate normal users on a pc to system on older OS that don’t use Windows 10 Apps

On windows 10 you can install version 8 only if you set the installer to Windows 7 or 8 , when testing that the update service was not installed

On the 7.x branch the update service was added on my test pc , but wasn’t visible on the 8 branch

Its recommended to stay on the newest version and use Windows 10 Apps when possible

For the workaround (that will break automatic updates but preserve security)

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Create a new Group Policy

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Go to Windows Settings , Security Settings , System Settings

Select the Skype Update Service and select disabled

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Verify its set to disabled

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Set the gpo filter for testing

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Link the gpo (testing to root acceptable)

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Run a gpupdate /force or wait a bit , after that the settings is set to disabled and cant be modified