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Description

Fodhelper.exe has a known UAC bypass as it attempts to look for specific registry keys upon execution, that do not exist. Therefore, an attacker can write its malicious commands in these registry keys to be executed by fodhelper.exe with the highest privilege. \

  1. HKCU:\Software\Classes\ms-settings\shell\open\command\
  2. HKCU:\Software\Classes\ms-settings\shell\open\command\DelegateExecute\
  3. HKCU:\Software\Classes\ms-settings\shell\open\command\(default)
    Upon triage, fodhelper.exe will have a child process and read access will occur on the registry keys. Isolate the endpoint and review parallel processes for additional behavior.
  • Type: TTP
  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
  • Datamodel: Endpoint
  • Last Updated: 2021-03-01
  • Author: Michael Haag, Splunk
  • ID: 909f8fd8-7ac8-11eb-a1f3-acde48001122

ATT&CK

ID Technique Tactic
T1112 Modify Registry Defense Evasion
T1548.002 Bypass User Account Control Privilege Escalation, Defense Evasion

| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where Processes.parent_process_name=fodhelper.exe by Processes.dest Processes.user Processes.parent_process Processes.process_name Processes.process Processes.process_id Processes.parent_process_id 
| `drop_dm_object_name(Processes)` 
| `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)` 
| `fodhelper_uac_bypass_filter`

Associated Analytic Story

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 node.

Required field

  • _time
  • Processes.parent_process_name
  • Processes.dest
  • Processes.user
  • Processes.parent_process
  • Processes.process_name
  • Processes.process
  • Processes.process_id
  • Processes.parent_process_id

Kill Chain Phase

  • Exploitation
  • Privilege Escalation

Known False Positives

Limited to no false positives are expected.

RBA

Risk Score Impact Confidence Message
81.0 90 90 Suspcious registy keys added by process fodhelper.exe (process_id- $process_id), with a parent_process of $parent_process_name$ that has been executed on $dest$ by $user$.

Reference

Test Dataset

Replay any dataset to Splunk Enterprise by using our replay.py tool or the UI. Alternatively you can replay a dataset into a Splunk Attack Range

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