Windows 8 firewall turned on automatically after updates

Hi there! I have a question about Windows 2008 updates. I updated my Windows and next morning and I noticed that the firewall of all my Windows 2008 R2 had been turned on. I believe GPO does not have policy that automatically enables Windows’ firewalls. Have any of you encountered the situation where the Windows 2008 Firewall is enabled on its own? I hope you can help me figure this out. Thank you.
