Detection rules › Splunk

Windows LOLBAS Executed Outside Expected Path

Status
production
Severity
low
Group by
IntegrityLevel, command_line, computer_name, event_action, original_file_name, parent_command_line, parent_process_guid, parent_process_id, parent_process_name, process_guid, process_hash, process_id, process_name, user, user_id, vendor_product
Author
Steven Dick
Source
github.com/splunk/security_content

The following analytic identifies a LOLBAS process being executed outside of it's expected location. Processes being executed outside of expected locations may be an indicator that an adversary is attempting to evade defenses or execute malicious code. The LOLBAS project documents Windows native binaries that can be abused by threat actors to perform tasks like executing malicious code.

Known false positives

  • Vendors, third party software or update processes may use versions of the binaries listed in the lookup table from non-standard paths. It is recommended to tune this analytic to exclude any known legitimate software or paths in your environment

MITRE ATT&CK coverage

Telemetry coverage

Rule body

name: Windows LOLBAS Executed Outside Expected Path
id: 326fdf44-b90c-4d2e-adca-1fd140b10536
version: 10
creation_date: '2024-05-03'
modification_date: '2026-05-13'
author: Steven Dick
status: production
type: Anomaly
description: |
    The following analytic identifies a LOLBAS process being executed outside of it's expected location.
    Processes being executed outside of expected locations may be an indicator that an adversary is attempting to evade defenses or execute malicious code.
    The LOLBAS project documents Windows native binaries that can be abused by threat actors to perform tasks like executing malicious code.
data_source:
    - Sysmon EventID 1
    - Windows Event Log Security 4688
search: |
    | tstats `security_content_summariesonly`
      count min(_time) as firstTime
            max(_time) as lastTime
      FROM datamodel=Endpoint.Processes where
    
      NOT Processes.process_path IN (
        "*\\PROGRA~*",
        "*\\Program Files \(x86\)\\",
        "*\\Program Files\\",
        "*:\\Windows\\System32\\*",
        "*:\\Windows\\SysWOW64\\*",
        "*:\\Windows\\WinSxS\\*"
      )
    
    by Processes.action Processes.dest Processes.original_file_name Processes.parent_process
       Processes.parent_process_exec Processes.parent_process_guid Processes.parent_process_id
       Processes.parent_process_name Processes.parent_process_path Processes.process
       Processes.process_exec Processes.process_guid Processes.process_hash
       Processes.process_id Processes.process_integrity_level Processes.process_name
       Processes.process_path Processes.user Processes.user_id Processes.vendor_product
    
    |`drop_dm_object_name(Processes)`
    | lookup lolbas_file_path lolbas_file_name as process_name OUTPUT description as desc
    | lookup lolbas_file_path lolbas_file_name as process_name lolbas_file_path as process_path OUTPUT description as is_lolbas_path
    | search desc!="false" AND is_lolbas_path="false"
    | `security_content_ctime(firstTime)`
    | `security_content_ctime(lastTime)`
    | `windows_lolbas_executed_outside_expected_path_filter`
how_to_implement: To implement this search, you must ingest logs that contain the process name and process path, such as with Sysmon EID 1.
known_false_positives: |
    Vendors, third party software or update processes may use versions of the binaries listed in the lookup table from non-standard paths.
    It is recommended to tune this analytic to exclude any known legitimate software or paths in your environment
references:
    - https://attack.mitre.org/techniques/T1036/
    - https://attack.mitre.org/techniques/T1036/005/
intermediate_findings:
    entities:
        - field: user
          type: user
          score: 20
          message: The user $user$ executed a LOLBAS [$process_name$] from an unexpected location [$process_path$] with CommandLine [$process$] on $dest$
        - field: dest
          type: system
          score: 20
          message: The user $user$ executed a LOLBAS [$process_name$] from an unexpected location [$process_path$] with CommandLine [$process$] on $dest$
threat_objects:
    - field: process_name
      type: process_name
analytic_story:
    - Living Off The Land
    - Masquerading - Rename System Utilities
    - Windows Defense Evasion Tactics
asset_type: Endpoint
mitre_attack_id:
    - T1036.005
    - T1218.011
product:
    - Splunk Enterprise
    - Splunk Enterprise Security
    - Splunk Cloud
category: endpoint
security_domain: endpoint

Stages and Predicates

Stage 1: tstats

| tstats `security_content_summariesonly`
  count min(_time) as firstTime
        max(_time) as lastTime
  FROM datamodel=Endpoint.Processes where

  NOT Processes.process_path IN (
    "*\\PROGRA~*",
    "*\\Program Files \(x86\)\\",
    "*\\Program Files\\",
    "*:\\Windows\\System32\\*",
    "*:\\Windows\\SysWOW64\\*",
    "*:\\Windows\\WinSxS\\*"
  )

by Processes.action Processes.dest Processes.original_file_name Processes.parent_process
   Processes.parent_process_exec Processes.parent_process_guid Processes.parent_process_id
   Processes.parent_process_name Processes.parent_process_path Processes.process
   Processes.process_exec Processes.process_guid Processes.process_hash
   Processes.process_id Processes.process_integrity_level Processes.process_name
   Processes.process_path Processes.user Processes.user_id Processes.vendor_product

Stage 2: search

| `drop_dm_object_name(Processes)`

Stage 3: lookup

| lookup lolbas_file_path lolbas_file_name as process_name OUTPUT description as desc
Lookup table
lolbas_file_path
Key field
lolbas_file_name as process_name
Output columns
['description', 'desc']

Stage 4: lookup

| lookup lolbas_file_path lolbas_file_name as process_name lolbas_file_path as process_path OUTPUT description as is_lolbas_path
Lookup table
lolbas_file_path
Key field
lolbas_file_name as process_name
Output columns
['description', 'is_lolbas_path']

Stage 5: search

| search desc!="false" AND is_lolbas_path="false"

Stage 6: search

| `security_content_ctime(firstTime)`

Stage 7: search

| `security_content_ctime(lastTime)`

Stage 8: search

| `windows_lolbas_executed_outside_expected_path_filter`

Exclusions

The rule actively suppresses these predicates.

FieldKindExcluded valuesSearch
Processes.process_pathin"*:\\Windows\\SysWOW64\\*", "*:\\Windows\\System32\\*", "*:\\Windows\\WinSxS\\*", "*\\PROGRA~*", "*\\Program Files \(x86\)\\", "*\\Program Files\\"excludes:Processes.process_path

Indicators

These rows show field, operator, and value matches.

FieldKindValuesSearch
descne
  • "false" corpus 2 (splunk 2)
field:"desc" kind:ne
is_lolbas_patheq
  • "false"
field:"is_lolbas_path" kind:eq