Sigma rule: LSASS Access Detected via Attack Surface Reduction

Rule

Title

LSASS Access Detected via Attack Surface Reduction

Status

test

Level

high

Author

Markus Neis

Date

2018-08-26

Modified

2022-08-13

File

rules/windows/builtin/windefend/win_defender_asr_lsass_access.yml

Commit

ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects Access to LSASS Process

Log source

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_*

False positives (as the rule lists them)

• Google Chrome GoogleUpdate.exe
• Some Taskmgr.exe related activity

Tags

• attack.credential-access
• attack.t1003.001

MITRE ATT&CK ids this rule names

• T1003.001

References

• https://learn.microsoft.com/en-us/defender-endpoint/attack-surface-reduction

Read on 2026-11-03T00:58:21.399Z under licence sigma-drl-1.1@d5f4c36a from https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules/windows/builtin/windefend/win_defender_asr_lsass_access.yml