Detectionmediumtest

Uncommon Extension Shim Database Installation Via Sdbinst.EXE

Detects installation of a potentially suspicious new shim with an uncommon extension using sdbinst.exe. Adversaries may establish persistence and/or elevate privileges by executing malicious content triggered by application shims

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Launch
Nasreddine Bencherchali (Nextron Systems)Created Tue Aug 01Updated Wed Jan 1018ee686c-38a3-4f65-9f44-48a077141f42windows
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 Logic5 selectors
detection:
    selection:
        - Image|endswith: '\sdbinst.exe'
        - OriginalFileName: 'sdbinst.exe'
    filter_main_legit_ext:
        CommandLine|contains: '.sdb'
    filter_main_legit_extensions:
        # ParentImage|endswith: ':\Windows\System32\svchost.exe'
        - CommandLine|endswith:
              - ' -c'
              - ' -f'
              - ' -mm'
              - ' -t'
        - CommandLine|contains: ' -m -bg'
    filter_main_null:
        CommandLine: null
    filter_main_empty:
        CommandLine: ''
    condition: selection and not 1 of filter_main_*
False Positives
Unknown

False positive likelihood has not been assessed. Additional context may be needed during triage.