Sigma rule: Potential Hidden Directory Creation Via NTFS INDEX_ALLOCATION Stream

Rule

Title

Potential Hidden Directory Creation Via NTFS INDEX_ALLOCATION Stream

Status

test

Level

medium

Author

Scoubi (@ScoubiMtl)

Date

2023-10-09

File

rules/windows/file/file_event/file_event_win_susp_hidden_dir_index_allocation.yml

Commit

ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects the creation of hidden file/folder with the "::$index_allocation" stream. Which can be used as a technique to prevent access to folder and files from tooling such as "explorer.exe" and "powershell.exe"

Log source

product

windows

category

file_event

Detection

selection:
    # Note: Both Sysmon and ETW are unable to log the presence of such streams in the CommandLine. But EDRs such as Crowdstrike are able to use e.g. CMD console history. Users are advised to test this before usage
    TargetFilename|contains: '::$index_allocation'
condition: selection

False positives (as the rule lists them)

• Unlikely

Tags

• attack.stealth
• attack.t1564.004

MITRE ATT&CK ids this rule names

• T1564.004

Related rules

• 0900463c-b33b-49a8-be1d-552a3b553dae (similar)

References

• https://twitter.com/pfiatde/status/1681977680688738305
• https://soroush.me/blog/2010/12/a-dotty-salty-directory-a-secret-place-in-ntfs-for-secret-files/
• https://sec-consult.com/blog/detail/pentesters-windows-ntfs-tricks-collection/
• https://github.com/redcanaryco/atomic-red-team/blob/5c3b23002d2bbede3c07e7307165fc2a235a427d/atomics/T1564.004/T1564.004.md#atomic-test-5---create-hidden-directory-via-index_allocation
• https://learn.microsoft.com/en-us/openspecs/windows_protocols/ms-fscc/c54dec26-1551-4d3a-a0ea-4fa40f848eb3

Read on 2026-11-03T00:58:21.399Z under licence sigma-drl-1.1@d5f4c36a from https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules/windows/file/file_event/file_event_win_susp_hidden_dir_index_allocation.yml