Adversaries may abuse time providers to execute DLLs when the system boots. The Windows Time service (W32Time) enables time synchronization across and within domains.(Citation: Microsoft W32Time Feb 2018) W32Time time providers are responsible for retrieving time stamps from hardware/network resources and outputting these values to other network clients.(Citation: Microsoft TimeProvider)

Time providers are implemented as dynamic-link libraries (DLLs) that are registered in the subkeys of `HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\W32Time\TimeProviders\`.(Citation: Microsoft TimeProvider) The time provider manager, directed by the service control manager, loads and starts time providers listed and enabled under this key at system startup and/or whenever parameters are changed.(Citation: Microsoft TimeProvider)

Adversaries may abuse this architecture to establish persistence, specifically by creating a new arbitrarily named subkey  pointing to a malicious DLL in the `DllName` value. Administrator privileges are required for time provider registration, though execution will run in context of the Local Service account.(Citation: Github W32Time Oct 2017)
Time Providers
source_name: mitre-attack  url: https://attack.mitre.org/techniques/T1547/003  external_id: T1547.003     source_name: Github W32Time Oct 2017  description: Lundgren, S. (2017, October 28). w32time. Retrieved March 26, 2018.  url: https://github.com/scottlundgren/w32time     source_name: Microsoft W32Time May 2017  description: Mathers, B. (2017, May 31). Windows Time Service Tools and Settings. Retrieved March 26, 2018.  url: https://docs.microsoft.com/windows-server/networking/windows-time-service/windows-time-service-tools-and-settings     source_name: Microsoft W32Time Feb 2018  description: Microsoft. (2018, February 1). Windows Time Service (W32Time). Retrieved March 26, 2018.  url: https://docs.microsoft.com/windows-server/networking/windows-time-service/windows-time-service-top     source_name: Microsoft TimeProvider  description: Microsoft. (n.d.). Time Provider. Retrieved March 26, 2018.  url: https://msdn.microsoft.com/library/windows/desktop/ms725475.aspx     source_name: TechNet Autoruns  description: Russinovich, M. (2016, January 4). Autoruns for Windows v13.51. Retrieved June 6, 2016.  url: https://technet.microsoft.com/en-us/sysinternals/bb963902     