Detectionhighexperimental

Suspicious File Write to SharePoint Layouts Directory

Detects suspicious file writes to SharePoint layouts directory which could indicate webshell activity or post-exploitation. This behavior has been observed in the exploitation of SharePoint vulnerabilities such as CVE-2025-49704, CVE-2025-49706 or CVE-2025-53770.

Convert In Phoenix Studio

Open this Sigma rule in the converter with the YAML preloaded and ready for backend selection.

Launch

Swachchhanda Shrawan Poudel (Nextron Systems)Created Thu Jul 241f0489be-b496-4ddf-b3a9-5900f2044e9cwindows

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:
        Image|endswith:
            - '\cmd.exe'
            - '\powershell_ise.exe'
            - '\powershell.exe'
            - '\pwsh.exe'
            - '\w3wp.exe'
        TargetFilename|startswith:
            - 'C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\'
            - 'C:\Program Files (x86)\Common Files\Microsoft Shared\Web Server Extensions\'
        TargetFilename|contains:
            - '\15\TEMPLATE\LAYOUTS\'
            - '\16\TEMPLATE\LAYOUTS\'
        TargetFilename|endswith:
            - '.asax'
            - '.ascx'
            - '.ashx'
            - '.asmx'
            - '.asp'
            - '.aspx'
            - '.bat'
            - '.cmd'
            - '.cer'
            - '.config'
            - '.hta'
            - '.js'
            - '.jsp'
            - '.jspx'
            - '.php'
            - '.ps1'
            - '.vbs'
    condition: selection