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Description

The following analytic detects when an executable known for User Account Control (UAC) bypass exploitation spawns a child process in a user-controlled location or a command shell executable (e.g., cmd.exe, powershell.exe). This detection leverages Sysmon EventID 1 data, focusing on high or system integrity level processes with specific parent-child process relationships. This activity is significant as it may indicate an attacker has successfully used a UAC bypass exploit to escalate privileges. If confirmed malicious, this could allow the attacker to execute arbitrary commands with elevated privileges, potentially compromising the entire system.

  • Type: TTP
  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
  • Datamodel: Endpoint
  • Last Updated: 2024-05-22
  • Author: Steven Dick
  • ID: 453a6b0f-b0ea-48fa-9cf4-20537ffdd22c

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1548 Abuse Elevation Control Mechanism Privilege Escalation, Defense Evasion
T1548.002 Bypass User Account Control Privilege Escalation, Defense Evasion
Kill Chain Phase
  • Exploitation
NIST
  • DE.CM
CIS20
  • CIS 10
CVE 


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| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where Processes.process_integrity_level IN ("high","system") AND Processes.parent_process_name IN (`uacbypass_process_name`) AND (Processes.process_name IN ("cmd.exe","powershell.exe","pwsh.exe","wscript","cscript.exe","bash.exe","werfault.exe") OR Processes.process IN ("*\\\\*","*\\Users\\*","*\\ProgramData\\*","*\\Temp\\*")) by Processes.dest, Processes.user, Processes.parent_process_guid, Processes.parent_process, Processes.parent_process_name Processes.process_name Processes.process, Processes.process_path, Processes.process_integrity_level, Processes.process_current_directory 
| `drop_dm_object_name(Processes)` 
| where parent_process_name != process_name 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `windows_uac_bypass_suspicious_child_process_filter`

Macros

The SPL above uses the following Macros:

:information_source: windows_uac_bypass_suspicious_child_process_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Required fields

List of fields required to use this analytic.

  • Processes.dest
  • Processes.user
  • Processes.parent_process_guid
  • Processes.parent_process
  • Processes.parent_process_name
  • Processes.process_name Processes.process
  • Processes.process_path
  • Processes.process_integrity_level
  • Processes.process_current_directory

How To Implement

Target environment must ingest sysmon data, specifically Event ID 1 with process integrity level data.

Known False Positives

Including Werfault.exe may cause some unintended false positives related to normal application faulting, but is used in a number of UAC bypass techniques.

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
45.0 60 75 A UAC bypass parent process- $parent_process_name$ on host- $dest$ launched a suspicious child process - $process_name$.

:information_source: The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

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

source | version: 2