Detectionmediumtest

Potential Hidden Directory Creation Via NTFS INDEX_ALLOCATION Stream - CLI

Detects command line containing reference to the "::$index_allocation" stream, which can be used as a technique to prevent access to folders or files from tooling such as "explorer.exe" or "powershell.exe"

Convert In Phoenix Studio

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

Launch
Nasreddine Bencherchali (Nextron Systems), ScoubiCreated Mon Oct 090900463c-b33b-49a8-be1d-552a3b553daewindows
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 Logic1 selector
detection:
    selection:
        # Note: Both Sysmon and ETW are unable to log the presence of such stream in the CommandLine. But EDRs such as Crowdstrike are able to using for example CMD console history. Users are advised to test this before usage
        CommandLine|contains: '::$index_allocation'
    condition: selection
False Positives
Unlikely

False positives are unlikely for most environments. High confidence detection.