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T1546.009 AppCert DLLs

Adversaries may establish persistence and/or elevate privileges by executing malicious content triggered by AppCert DLLs loaded into processes. Dynamic-link libraries (DLLs) that are specified in the AppCertDLLs Registry key under HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Session Manager\ are loaded into every process that calls the ubiquitously used application programming interface (API) functions CreateProcess, CreateProcessAsUser, CreateProcessWithLoginW, CreateProcessWithTokenW, or WinExec. 1

Similar to Process Injection, this value can be abused to obtain elevated privileges by causing a malicious DLL to be loaded and run in the context of separate processes on the computer. Malicious AppCert DLLs may also provide persistence by continuously being triggered by API activity.

Item Value
ID T1546.009
Sub-techniques T1546.001, T1546.002, T1546.003, T1546.004, T1546.005, T1546.006, T1546.007, T1546.008, T1546.009, T1546.010, T1546.011, T1546.012, T1546.013, T1546.014, T1546.015, T1546.016, T1546.017, T1546.018
Tactics TA0004, TA0003
Platforms Windows
Version 1.1
Created 24 January 2020
Last Modified 24 October 2025

Procedure Examples

ID Name Description
S0196 PUNCHBUGGY PUNCHBUGGY can establish using a AppCertDLLs Registry key.10

Mitigations

ID Mitigation Description
M1038 Execution Prevention Adversaries install new AppCertDLL binaries to execute this technique. Identify and block potentially malicious software executed through AppCertDLLs functionality by using application control 4 tools, like Windows Defender Application Control6, AppLocker, 9 8 or Software Restriction Policies 5 where appropriate. 7

References

  1. Hosseini, A. (2017, July 18). Ten Process Injection Techniques: A Technical Survey Of Common And Trending Process Injection Techniques. Retrieved December 7, 2017. ↩

  2. Microsoft. (2007, October 24). Windows Sysinternals - AppCertDlls. Retrieved November 17, 2024. ↩

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

  4. Beechey, J. (2010, December). Application Whitelisting: Panacea or Propaganda?. Retrieved November 18, 2014. ↩

  5. Corio, C., & Sayana, D. P. (2008, June). Application Lockdown with Software Restriction Policies. Retrieved September 12, 2024. ↩

  6. Gorzelany, A., Hall, J., Poggemeyer, L.. (2019, January 7). Windows Defender Application Control. Retrieved July 16, 2019. ↩

  7. Microsoft. (2012, June 27). Using Software Restriction Policies and AppLocker Policies. Retrieved April 7, 2016. ↩

  8. NSA Information Assurance Directorate. (2014, August). Application Whitelisting Using Microsoft AppLocker. Retrieved March 31, 2016. ↩

  9. Tomonaga, S. (2016, January 26). Windows Commands Abused by Attackers. Retrieved February 2, 2016. ↩

  10. Elovitz, S. & Ahl, I. (2016, August 18). Know Your Enemy: New Financially-Motivated & Spear-Phishing Group. Retrieved February 26, 2018. ↩