Hidden Executable In NTFS Alternate Data Stream

Status: test
Severity: medium
Log source: product windows, category create_stream_hash
Author: Florian Roth (Nextron Systems), @0xrawsec
Source: github.com/SigmaHQ/sigma

Detects the creation of an ADS (Alternate Data Stream) that contains an executable by looking at a non-empty Imphash

MITRE ATT&CK coverage

Tactic	Techniques
Stealth	`T1564.004` Hide Artifacts: NTFS File Attributes

Event coverage

Provider	Event	Title
Sysmon	Event ID 15	FileCreateStreamHash

Rule body yaml

title: Hidden Executable In NTFS Alternate Data Stream
id: b69888d4-380c-45ce-9cf9-d9ce46e67821
status: test
description: Detects the creation of an ADS (Alternate Data Stream) that contains an executable by looking at a non-empty Imphash
references:
    - https://twitter.com/0xrawsec/status/1002478725605273600?s=21
author: Florian Roth (Nextron Systems), @0xrawsec
date: 2018-06-03
modified: 2023-02-10
tags:
    - attack.stealth
    - attack.s0139
    - attack.t1564.004
logsource:
    product: windows
    category: create_stream_hash
    definition: 'Requirements: Sysmon or equivalent configured with Imphash logging'
detection:
    selection:
        Hash|contains: 'IMPHASH='
    filter_main_null:
        Hash|contains: 'IMPHASH=00000000000000000000000000000000'
    condition: selection and not 1 of filter_main_*
falsepositives:
    - This rule isn't looking for any particular binary characteristics. As legitimate installers and programs were seen embedding hidden binaries in their ADS. Some false positives are expected from browser processes and similar.
level: medium

Stages and Predicates

Stage 0: `condition`

selection and not 1 of filter_main_*

Stage 1: `selection`

selection:
    Hash|contains: 'IMPHASH='

Stage 2: `not filter_main_null`

filter_main_null:
    Hash|contains: 'IMPHASH=00000000000000000000000000000000'

Exclusions

Top-level NOT(...) conjuncts: predicates this rule actively suppresses.

Field	Kind	Excluded values
`Hash`	match	`IMPHASH=00000000000000000000000000000000`

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

Field	Kind	Values
`Hash`	match	`IMPHASH=`

`j` / `k`	Scroll down / up
`d` / `u`	Half-page down / up
`gg` / `G`	Top / bottom
`h` / `l`	History back / forward
`f`	Follow link (`Shift` = new tab)
`/`	Focus search
`?`	Toggle this help
`↑` / `↓`	Navigate search results
`Enter`	Open highlighted result
`Esc`	Close results / dialog

`type:`	`events` / `rules` / `providers`
`vendor:`	`sigma` / `elastic` / `splunk` / `kusto` / `chronicle` (vendor name alone also works: `sigma:`, `kql:`, `secops:`…)
`tactic:`	TA-id, slug, or name: `credential_access`, `TA0006`
`technique:`	technique or sub-technique ID: `T1003`, `T1003.001` (alias `tech:`)
`severity:`	`critical` / `high` / `medium` / `low` / `informational` (alias `sev:`)
`risk_score`	Numeric comparison on the Elastic risk score (0 to 100): `risk_score>50`, `risk_score<=20`, `risk_score=99` (alias `risk`; Elastic rules only)
`stages:`	Rules with exactly N pipeline stages
`correlation:`	`single_event` / `sequence` / `alternatives` / `alternatives_cross_log` / `all_required` / `correlated`
`with:`	Co-occurrence event-id; stacks (`with:4624 with:4769`) to require all, while a comma list in one occurrence (`with:4624,4769`) is an either-or group. Implies multi-event
`like:`	Structural neighbors of a rule slug (equivalents + subsumption stricter / broader): `like:comsvcs_lsass_memory_dump-splunk-sysmon`
`groupby:`	Entity-grouping substring match against `group_by_keys`: `groupby:user`, `groupby:host`
`uses:`	Rules whose predicate tree touches the field (any kind, any value): `uses:CommandLine`
`excludes:`	Rules with top-level `not()` clauses on the field (FP whitelists): `excludes:ParentImage`
`field:` / `value:`	Predicate search; narrows rule cards to those with a matching leaf and drives the indicator tier. Unquoted = substring, wildcards allowed (`value:mimikatz`)
`indicator:`	Shorthand for `field:F value:V`: `indicator:Image=*\powershell.exe`
`kind:`	Filter by predicate kind. Narrows rule cards to those carrying a matching predicate leaf (`vendor:elastic kind:cidr_match`) and drives the indicator tier: `contains` / `starts_with` / `ends_with` / `regex` / `cidr` / `eq` / `in` … (operator aliases `op:`/`match:`)
`has:` / `no:`	`sample`, `field`, `notes`, `refs`, `trace`, `thirdparty`, `rule`, `pattern`, `timewindow`, `threshold`, `newterms`, `sigma`/`elastic`/`splunk`/`kusto`/`chronicle`
`-op:val`	Exclude matches; works on most operators but not `type:`/`like:`/`has:`/`no:` (use `no:<flag>` to exclude a rule flag): `tactic:execution -vendor:splunk`. Standalone `-kind:`/`-field:`/`-value:` drop every rule carrying a matching predicate leaf (`type:rules -kind:is_null`)
`field:"…"` / `value:"…"`	Quoted value = anchored exact match (also allows spaces): `value:"net user"`
`a,b`	Comma = OR inside one operator (`vendor:sigma,elastic`, `severity:high,critical`); repeating a facet merges the same way. `field:`/`value:` never split (literal commas)
`vendors:` / `stage:`	Singular and plural spellings fold to the canonical operator and value: `tactics:` = `tactic:`, `type:event` = `type:events`, `correlation:sequences` = `correlation:sequence`, `has:thresholds` = `has:threshold`
`"quoted phrase"`	Exact-match a multi-word phrase (free text)

Hidden Executable In NTFS Alternate Data Stream

MITRE ATT&CK coverage

Event coverage

Rule body yaml

Stages and Predicates

Stage 0: `condition`

Stage 1: `selection`

Stage 2: `not filter_main_null`

Exclusions

Indicators

Keyboard shortcuts

Search operators

Hidden Executable In NTFS Alternate Data Stream

MITRE ATT&CK coverage

Event coverage

Rule body yaml

Stages and Predicates

Stage 0: condition

Stage 1: selection

Stage 2: not filter_main_null

Exclusions

Indicators

Stage 0: `condition`

Stage 1: `selection`

Stage 2: `not filter_main_null`