Detectionhighexperimental

Legitimate Application Writing Files In Uncommon Location

Detects legitimate applications writing any type of file to uncommon or suspicious locations that are not typical for application data storage or execution. Adversaries may leverage legitimate applications (Living off the Land Binaries - LOLBins) to drop or download malicious files to uncommon locations on the system to evade detection by security solutions.

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Launch

Swachchhanda Shrawan Poudel (Nextron Systems)Created Wed Dec 101cf465a1-2609-4c15-9b66-c32dbe4bfd67windows

Log Source

WindowsFile Event

ProductWindows← raw: windows

CategoryFile Event← raw: file_event

Events for file system activity including creation, modification, and deletion.

Detection Logic

detection:
    selection_img:
        Image|endswith:
            # Microsoft Office Programs Dropping Executables / Rest of the apps are covered in: c7a74c80-ba5a-486e-9974-ab9e682bc5e4
            - '\eqnedt32.exe'
            - '\wordpad.exe'
            - '\wordview.exe'
            # LOLBINs that can be used to download executables
            - '\cmdl32.exe'
            - '\certutil.exe'
            - '\certoc.exe'
            - '\CertReq.exe'
            - '\bitsadmin.exe'
            - '\Desktopimgdownldr.exe'
            - '\esentutl.exe'
            - '\expand.exe'
            - '\extrac32.exe'
            - '\replace.exe'
            - '\mshta.exe'
            - '\ftp.exe'
            - '\Ldifde.exe'
            - '\RdrCEF.exe'
            - '\hh.exe'
            - '\finger.exe'
            - '\findstr.exe'
    selection_locations:
        TargetFilename|contains:
            - ':\Perflogs'
            - ':\ProgramData\'
            - ':\Temp\'
            - ':\Users\Public\'
            - ':\Windows\'
            - '\$Recycle.Bin\'
            - '\AppData\Local\'
            - '\AppData\Roaming\'
            - '\Contacts\'
            - '\Desktop\'
            - '\Favorites\'
            - '\Favourites\'
            - '\inetpub\wwwroot\'
            - '\Music\'
            - '\Pictures\'
            - '\Start Menu\Programs\Startup\'
            - '\Users\Default\'
            - '\Videos\'
    condition: all of selection_*