title: LSASS Access Detected via Attack Surface Reduction
id: a0a278fe-2c0e-4de2-ac3c-c68b08a9ba98
description: Detects Access to LSASS Process
status: experimental
references:
    - https://docs.microsoft.com/en-us/windows/security/threat-protection/windows-defender-exploit-guard/attack-surface-reduction-exploit-guard?WT.mc_id=twitter
author: Markus Neis
date: 2018/08/26
modified: 2022/02/09
tags:
    - attack.credential_access
# Defender Attack Surface Reduction
    - attack.t1003.001
logsource:
    product: windows
    service: windefend
    definition: 'Requirements:Enabled Block credential stealing from the Windows local security authority subsystem (lsass.exe) from Attack Surface Reduction (GUID: 9e6c4e1f-7d60-472f-ba1a-a39ef669e4b2)'
detection:
    selection:
        EventID: 1121
        Path|endswith: '\lsass.exe'
    filter_thor:
        ProcessName|startswith: 'C:\Windows\Temp\asgard2-agent\'
        ProcessName|endswith:
            - '\thor64.exe'
            - '\thor.exe'
    filter_exact:
        ProcessName:
            - 'C:\Windows\System32\atiesrxx.exe'
            - 'C:\Windows\System32\CompatTelRunner.exe'
            - 'C:\Windows\System32\msiexec.exe'
            - 'C:\Windows\System32\nvwmi64.exe'
            - 'C:\Windows\System32\svchost.exe'
            - 'C:\Windows\System32\Taskmgr.exe'
            - 'C:\Windows\System32\wbem\WmiPrvSE.exe'
            - 'C:\Windows\SysWOW64\msiexec.exe'
    filter_begins:
        ProcessName|startswith:
            - 'C:\Windows\System32\\DriverStore\'
            - 'C:\WINDOWS\Installer\'
            - 'C:\Program Files\'
            - 'C:\Program Files (x86)\'
    condition: selection and not 1 of filter_*
falsepositives:
    - Google Chrome GoogleUpdate.exe
    - Some Taskmgr.exe related activity
level: high