Detectionmediumtest

WinRAR Execution in Non-Standard Folder

Detects a suspicious WinRAR execution in a folder which is not the default installation folder

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Florian Roth (Nextron Systems), TigzyCreated Wed Nov 17Updated Wed Jul 164ede543c-e098-43d9-a28f-dd784a13132fwindows

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:
        - Image|endswith:
              - '\rar.exe'
              - '\winrar.exe'
        - Description:
              - 'Command line RAR'
              - 'WinRAR'
    filter_main_unrar:
        # Note: we filter unrar as it has the same description as the other utilities, and we're only interested in compression
        Image|endswith: '\UnRAR.exe'
    filter_main_path:
        Image|contains:
            - ':\Program Files (x86)\WinRAR\'
            - ':\Program Files\WinRAR\'
    filter_optional_temp:
        # Note: in some occasion installers were seen dropping "rar" in TEMP
        Image|contains: ':\Windows\Temp\'
    condition: selection and not 1 of filter_main_* and not 1 of filter_optional_*