Renamed AutoIt Execution

Status: test
Severity: high
Log source: product windows, category process_creation
Author: Florian Roth (Nextron Systems)
Source: github.com/SigmaHQ/sigma

Detects the execution of a renamed AutoIt2.exe or AutoIt3.exe. AutoIt is a scripting language and automation tool for Windows systems. While primarily used for legitimate automation tasks, it can be misused in cyber attacks. Attackers can leverage AutoIt to create and distribute malware, including keyloggers, spyware, and botnets. A renamed AutoIt executable is particularly suspicious.

MITRE ATT&CK coverage

Tactic	Techniques
Stealth	`T1027` Obfuscated Files or Information

Event coverage

Provider	Event	Title
Sysmon	Event ID 1	Process creation

Rule body yaml

title: Renamed AutoIt Execution
id: f4264e47-f522-4c38-a420-04525d5b880f
status: test
description: |
    Detects the execution of a renamed AutoIt2.exe or AutoIt3.exe.
    AutoIt is a scripting language and automation tool for Windows systems. While primarily used for legitimate automation tasks, it can be misused in cyber attacks.
    Attackers can leverage AutoIt to create and distribute malware, including keyloggers, spyware, and botnets. A renamed AutoIt executable is particularly suspicious.
references:
    - https://twitter.com/malmoeb/status/1665463817130725378?s=12&t=C0_T_re0wRP_NfKa27Xw9w
    - https://www.autoitscript.com/site/
author: Florian Roth (Nextron Systems)
date: 2023-06-04
modified: 2024-11-23
tags:
    - attack.stealth
    - attack.t1027
logsource:
    category: process_creation
    product: windows
detection:
    selection_1:
        CommandLine|contains:
            - ' /AutoIt3ExecuteScript'
            - ' /ErrorStdOut'
    selection_2:
        Hashes|contains:
            - 'IMPHASH=FDC554B3A8683918D731685855683DDF'  # AutoIt v2 - doesn't cover all binaries
            - 'IMPHASH=CD30A61B60B3D60CECDB034C8C83C290'  # AutoIt v2 - doesn't cover all binaries
            - 'IMPHASH=F8A00C72F2D667D2EDBB234D0C0AE000'  # AutoIt v3 - doesn't cover all binaries
    selection_3:
        OriginalFileName:
            - 'AutoIt3.exe'
            - 'AutoIt2.exe'
            - 'AutoIt.exe'
    filter_main_legit_name:
        Image|endswith:
            - '\AutoIt.exe'
            - '\AutoIt2.exe'
            - '\AutoIt3_x64.exe'
            - '\AutoIt3.exe'
    condition: 1 of selection_* and not 1 of filter_main_*
falsepositives:
    - Unknown
level: high

Stages and Predicates

Stage 0: `condition`

1 of selection_* and not 1 of filter_main_*

Stage 1: `selection_1`

selection_1:
    CommandLine|contains:
        - ' /AutoIt3ExecuteScript'
        - ' /ErrorStdOut'

Stage 2: `selection_2`

selection_2:
    Hashes|contains:
        - 'IMPHASH=FDC554B3A8683918D731685855683DDF'
        - 'IMPHASH=CD30A61B60B3D60CECDB034C8C83C290'
        - 'IMPHASH=F8A00C72F2D667D2EDBB234D0C0AE000'

Stage 3: `selection_3`

selection_3:
    OriginalFileName:
        - 'AutoIt3.exe'
        - 'AutoIt2.exe'
        - 'AutoIt.exe'

Stage 4: `not filter_main_legit_name`

filter_main_legit_name:
    Image|endswith:
        - '\AutoIt.exe'
        - '\AutoIt2.exe'
        - '\AutoIt3_x64.exe'
        - '\AutoIt3.exe'

Exclusions

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

Field	Kind	Excluded values
`Image`	ends_with	`\AutoIt.exe`
`Image`	ends_with	`\AutoIt2.exe`
`Image`	ends_with	`\AutoIt3.exe`
`Image`	ends_with	`\AutoIt3_x64.exe`

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
`CommandLine`	match	`/AutoIt3ExecuteScript` `/ErrorStdOut`
`Hashes`	match	`IMPHASH=CD30A61B60B3D60CECDB034C8C83C290` `IMPHASH=F8A00C72F2D667D2EDBB234D0C0AE000` `IMPHASH=FDC554B3A8683918D731685855683DDF`
`OriginalFileName`	eq	`AutoIt.exe` `AutoIt2.exe` `AutoIt3.exe` corpus 2 (sigma 2)

`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)

Renamed AutoIt Execution

MITRE ATT&CK coverage

Event coverage

Rule body yaml

Stages and Predicates

Stage 0: `condition`

Stage 1: `selection_1`

Stage 2: `selection_2`

Stage 3: `selection_3`

Stage 4: `not filter_main_legit_name`

Exclusions

Indicators

Keyboard shortcuts

Search operators

Renamed AutoIt Execution

MITRE ATT&CK coverage

Event coverage

Rule body yaml

Stages and Predicates

Stage 0: condition

Stage 1: selection_1

Stage 2: selection_2

Stage 3: selection_3

Stage 4: not filter_main_legit_name

Exclusions

Indicators

Stage 0: `condition`

Stage 1: `selection_1`

Stage 2: `selection_2`

Stage 3: `selection_3`

Stage 4: `not filter_main_legit_name`