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T1547.003 Time Providers

Adversaries may abuse time providers to execute DLLs when the system boots. The Windows Time service (W32Time) enables time synchronization across and within domains.3 W32Time time providers are responsible for retrieving time stamps from hardware/network resources and outputting these values to other network clients.4

Time providers are implemented as dynamic-link libraries (DLLs) that are registered in the subkeys of HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\W32Time\TimeProviders\.4 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.4

Adversaries may abuse this architecture to establish persistence, specifically by registering and enabling a malicious DLL as a time provider. Administrator privileges are required for time provider registration, though execution will run in context of the Local Service account.1

Item Value
ID T1547.003
Sub-techniques T1547.001, T1547.002, T1547.003, T1547.004, T1547.005, T1547.006, T1547.007, T1547.008, T1547.009, T1547.010, T1547.012, T1547.013, T1547.014, T1547.015
Tactics TA0003, TA0004
Platforms Windows
Permissions required Administrator, SYSTEM
Version 1.0
Created 24 January 2020
Last Modified 20 April 2022

Mitigations

ID Mitigation Description
M1022 Restrict File and Directory Permissions Consider using Group Policy to configure and block additions/modifications to W32Time DLLs. 2
M1024 Restrict Registry Permissions Consider using Group Policy to configure and block modifications to W32Time parameters in the Registry. 2

Detection

ID Data Source Data Component
DS0017 Command Command Execution
DS0011 Module Module Load
DS0009 Process Process Creation
DS0024 Windows Registry Windows Registry Key Modification

References

  1. Lundgren, S. (2017, October 28). w32time. Retrieved March 26, 2018. ↩

  2. Mathers, B. (2017, May 31). Windows Time Service Tools and Settings. Retrieved March 26, 2018. ↩↩

  3. Microsoft. (2018, February 1). Windows Time Service (W32Time). Retrieved March 26, 2018. ↩

  4. Microsoft. (n.d.). Time Provider. Retrieved March 26, 2018. ↩↩↩

  5. Russinovich, M. (2016, January 4). Autoruns for Windows v13.51. Retrieved June 6, 2016. ↩