name: Windows InstallUtil Remote Network Connection
id: 4fbf9270-43da-11ec-9486-acde48001122
version: 2
date: '2022-03-16'
author: Michael Haag, Splunk
status: production
type: TTP
description: 'The following analytic identifies the Windows InstallUtil.exe binary
  making a remote network connection. This technique may be used to download and execute
  code while bypassing application control. 

  When `InstallUtil.exe` is used in a malicous manner, the path to an executable on
  the filesystem is typically specified. Take note of the parent process. In a suspicious
  instance, this will be spawned from a non-standard process like `Cmd.exe`, `PowerShell.exe`
  or `Explorer.exe`. 

  If used by a developer, typically this will be found with multiple command-line
  switches/arguments and spawn from Visual Studio. 

  During triage review resulting network connections, file modifications, and parallel
  processes. Capture any artifacts and review further.'
data_source:
- Sysmon Event ID 1
search:
  selection1:
    OriginalFileName: InstallUtil.exe
  selection2:
    Image|endswith: installutil.exe
  condition: (selection1 or selection2)
how_to_implement: To successfully implement this search you need to be ingesting information
  on process that include the name of the process responsible for the changes from
  your endpoints into the `Endpoint` datamodel in the `Processes` and `Ports` node.
  In addition, confirm the latest CIM App 4.20 or higher is installed and the latest
  TA for the endpoint product.
known_false_positives: Limited false positives should be present as InstallUtil is
  not typically used to download remote files. Filter as needed based on Developers
  requirements.
references:
- https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1218.004/T1218.004.md
tags:
  analytic_story:
  - Signed Binary Proxy Execution InstallUtil
  - Living Off The Land
  asset_type: Endpoint
  confidence: 100
  impact: 80
  message: An instance of $parent_process_name$ spawning $process_name$ was identified
    on endpoint $dest$ by user $user$ generating a remote download.
  mitre_attack_id:
  - T1218.004
  - T1218
  observable:
  - name: user
    type: User
    role:
    - Victim
  - name: dest
    type: Hostname
    role:
    - Victim
  - name: parent_process_name
    type: Process
    role:
    - Parent Process
  - name: process_name
    type: Process
    role:
    - Child Process
  product:
  - Splunk Enterprise
  - Splunk Enterprise Security
  - Splunk Cloud
  risk_score: 80
  security_domain: endpoint
tests:
- name: True Positive Test
  attack_data:
  - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1218.004/atomic_red_team/windows-sysmon.log
    source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
    sourcetype: xmlwineventlog