Emerging Threathightest

Pikabot Fake DLL Extension Execution Via Rundll32.EXE

Detects specific process tree behavior linked to "rundll32" executions, wherein the associated DLL lacks a common ".dll" extension, often signaling potential Pikabot activity.

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Launch

Swachchhanda Shrawan Poudel, Nasreddine Bencherchali (Nextron Systems)Created Fri Jan 261bf0ba65-9a39-42a2-9271-31d31bf2f0bf2023

Emerging Threat

Active Threat

Developed to detect an active or emerging threat. Prioritize investigation of any alerts and correlate with threat intelligence.

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:
    selection:
        ParentImage|endswith:
            - '\cmd.exe'
            - '\cscript.exe'
            - '\mshta.exe'
            - '\powershell.exe'
            - '\pwsh.exe'
            - '\regsvr32.exe'
            - '\wscript.exe'
        Image|endswith: '\rundll32.exe'
        CommandLine|contains:
            - ':\ProgramData\'
            - ':\Users\Public\'
            - ':\Windows\Installer\'
            - '\AppData\Local\Temp\'
            - '\AppData\Roaming\'
    filter_main_known_extension:
        - CommandLine|contains:
              - '.cpl '
              - '.cpl,'
              - '.dll '
              - '.dll,'
              - '.inf '
              - '.inf,'
        - CommandLine|endswith:
              - '.cpl'
              - '.cpl"'
              - '.dll'
              - '.dll"'
              - '.inf'
              - '.inf"'
              - ".cpl'"
              - ".dll'"
              - ".inf'"
    condition: selection and not 1 of filter_main_*