Detectionmediumtest

Potential Persistence Via New AMSI Providers - Registry

Detects when an attacker adds a new AMSI provider via the Windows Registry to bypass AMSI (Antimalware Scan Interface) protections. Attackers may add custom AMSI providers to persist on the system and evade detection by security software that relies on AMSI for scanning scripts and other content. This technique is often used in conjunction with fileless malware and script-based attacks to maintain persistence while avoiding detection.

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Launch

Nasreddine Bencherchali (Nextron Systems)Created Thu Jul 21Updated Sun Oct 2633efc23c-6ea2-4503-8cfe-bdf82ce8f705windows

Log Source

WindowsRegistry Set

ProductWindows← raw: windows

CategoryRegistry Set← raw: registry_set

Detection Logic

detection:
    selection:
        TargetObject|contains:
            - '\SOFTWARE\Microsoft\AMSI\Providers\'
            - '\SOFTWARE\WOW6432Node\Microsoft\AMSI\Providers\'
    filter_optional_avast:
        Image:
            - 'C:\Program Files\Avast Software\Avast\RegSvr.exe'
            - 'C:\Program Files\Avast Software\Avast\x86\RegSvr.exe'
        TargetObject|contains: '\{FB904E4E-D2C7-4C8D-8492-B620BB9896B1}'
    filter_optional_avg:
        Image:
            - 'C:\Program Files\AVG\Antivirus\RegSvr.exe'
            - 'C:\Program Files\AVG\Antivirus\x86\RegSvr.exe'
        TargetObject|contains: '\{FB904E4E-D2C7-4C8D-8492-B620BB9896B1}'
    filter_optional_avira:
        Image: 'C:\Program Files\Avira\Endpoint Protection SDK\endpointprotection.exe'
        TargetObject|contains: '\{00000001-3DCC-4B48-A82E-E2071FE58E05}'
    condition: selection and not 1 of filter_optional_*