Detection rules › Splunk

Mock System Directory - Windows (Windows Event Log)

Group by
_time, host
Source
github.com/anvilogic-forge/armory

A Windows User Account Control Bypass technique is capable of achieving privilege escalation without displaying a UAC prompt. This method involves creating a mock directory with a trailing whitespace and the same name as a legitmate trusted location (e.g. "C:\Windows \System32") and copying required files to it. The mock directory can not be created via Windows Explorer, requiring the attacker to create it via scripting or command line. This use case detects process or parent process file paths (where available depending on log source) for trusted system directories (\Windows\system32 or Program Files) including a trailing space before .

MITRE ATT&CK coverage

References

Telemetry coverage

Rule body

id: '33428.59206'
title: Mock System Directory - Windows
description: A Windows User Account Control Bypass technique is capable of achieving
  privilege escalation without displaying a UAC prompt. This method involves creating
  a mock directory with a trailing whitespace and the same name as a legitmate trusted
  location (e.g. "C:\Windows \System32\") and copying required files to it. The mock
  directory can not be created via Windows Explorer, requiring the attacker to create
  it via scripting or command line. This use case detects process or parent process
  file paths (where available depending on log source) for trusted system directories
  (\Windows\system32 or Program Files) including a trailing space before \.
logic_format: Splunk
logic: '`get_endpoint_data` `get_endpoint_data_winevent` (TERM(EventCode=4688) OR
  "<EventID>4688<" OR Type=Process) "Windows " OR ("Program " "Files ") OR ("Program
  " "Files" "\(x86\) ") | where match(process_path, "(?i)\s+\x5c") or match(parent_process_path,
  "(?i)\s+\x5c")| table _time, host, user, process, process_*, parent_process, parent_process_*
  | bin span=1s | stats values(*) as * by _time, host '
techniques:
- privilege-escalation:abuse elevation control mechanism:bypass user account control
- defense-evasion:abuse elevation control mechanism:bypass user account control
- defense-evasion:masquerading
technique_id:
- T1548.002
- T1036
data_category:
- Windows event logs
references:
- https://borncity.com/win/2023/03/11/windows-10-11-mock-folders-as-uac-bypass-security-disaster-leverage-applocker-and-srp/
- https://www.fortinet.com/blog/threat-research/fickle-stealer-distributed-via-multiple-attack-chain

Stages and Predicates

Stage 1: search

`get_endpoint_data` `get_endpoint_data_winevent` (TERM(EventCode=4688) OR "<EventID>4688<" OR Type=Process) "Windows " OR ("Program " "Files ") OR ("Program " "Files" "\(x86\) ")

Stage 2: where

| where match(process_path, "(?i)\s+\x5c") or match(parent_process_path, "(?i)\s+\x5c")

Stage 3: table

| table _time, host, user, process, process_*, parent_process, parent_process_*

Stage 4: bucket

| bin span=1s

Stage 5: stats

| stats values(*) as * by _time, host

Indicators

These rows show field, operator, and value matches.

FieldKindValuesSearch
EventCodeeq
  • 4688 corpus 317 (splunk 283, kusto 33, elastic 1)
field:"EventID" kind:eq value:"4688"
parent_process_pathregex_match
  • "(?i)\s+\x5c" corpus 2 (splunk 2)
field:"parent_process_name" kind:regex_match
process_pathregex_match
  • "(?i)\s+\x5c" corpus 2 (splunk 2)
field:"process_name" kind:regex_match

Search terms

These SPL tokens match against raw event text.

StageTerm
1"<EventID>4688<"
1"Windows "
1"Program "
1"Files "
1"Program "
1"Files"
1"\(x86\) "