Detectionhightest

Disable Windows Defender AV Security Monitoring

Detects attackers attempting to disable Windows Defender using Powershell

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ok invrep-de, oscd.community, François HubautCreated Mon Oct 12Updated Fri Nov 18a7ee1722-c3c5-aeff-3212-c777e4733217windows
Log Source
WindowsProcess Creation
ProductWindows← raw: windows
CategoryProcess Creation← raw: process_creation

Events generated when a new process is spawned on the system. Covers command-line arguments, parent/child relationships, and process metadata.

Detection Logic
Detection Logic6 selectors
detection:
    selection_pwsh_binary:
        - Image|endswith:
              - '\powershell.exe'
              - '\pwsh.exe'
        - OriginalFileName:
              - 'PowerShell.EXE'
              - 'pwsh.dll'
    selection_pwsh_cli:
        CommandLine|contains:
            - '-DisableBehaviorMonitoring $true'
            - '-DisableRuntimeMonitoring $true'
    selection_sc_binary:
        - Image|endswith: '\sc.exe'
        - OriginalFileName: 'sc.exe'
    selection_sc_tamper_cmd_stop:
        CommandLine|contains|all:
            - 'stop'
            - 'WinDefend'
    selection_sc_tamper_cmd_delete:
        CommandLine|contains|all:
            - 'delete'
            - 'WinDefend'
    selection_sc_tamper_cmd_disabled:
        CommandLine|contains|all:
            - 'config'
            - 'WinDefend'
            - 'start=disabled'
    condition: all of selection_pwsh_* or (selection_sc_binary and 1 of selection_sc_tamper_*)
False Positives

Minimal, for some older versions of dev tools, such as pycharm, developers were known to sometimes disable Windows Defender to improve performance, but this generally is not considered a good security practice.

Rule Metadata
Rule ID
a7ee1722-c3c5-aeff-3212-c777e4733217
Status
test
Level
high
Type
Detection
Created
Mon Oct 12
Modified
Fri Nov 18
Path
rules/windows/process_creation/proc_creation_win_powershell_disable_defender_av_security_monitoring.yml
Raw Tags
attack.defense-evasionattack.t1562.001
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