Detection rules › Splunk

Indirect Command Execution (Sysmon)

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

An adversary may use default tools, usually not restricted, to gain execution without using cmd

MITRE ATT&CK coverage

References

Telemetry coverage

ProviderRecord / event type
SysmonEvent ID 1: Process creation

Rule body

id: '5971.18224'
title: Indirect Command Execution
description: 'An adversary may use default tools, usually not restricted, to gain
  execution without using cmd. Threat Actor Association: Andariel, APT28 - Software
  Association: IcedId - Atomics T1548.002 Test#3 Atomics T1202 Test #1 Atomics T1202
  Test #2'
logic_format: Splunk
logic: '`get_endpoint_data` `get_endpoint_data_sysmon` ("EventCode=1" OR "<EventID>1<")
  (TERM(forfiles) OR TERM(fodhelper) OR TERM(ftp) OR TERM(pcalua)) | regex parent_process_name="(?i)(forfiles|fodhelper|ftp|pcalua)\.exe"
  | table _time, host, user parent_*, process, process_*, signature_id | bin span=1s
  | stats values(*) as * by _time, host '
techniques:
- defense-evasion:indirect command execution
- privilege-escalation:abuse elevation control mechanism
technique_id: 
- T1202
- T1548
data_category:
- Windows Sysmon
references:
- https://pentestlab.blog/tag/pcalua-exe/
- https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1202/T1202.md#atomic-test-1---indirect-command-execution---pcaluaexe

Stages and Predicates

Stage 1: search

`get_endpoint_data` `get_endpoint_data_sysmon` ("EventCode=1" OR "<EventID>1<") (TERM(forfiles) OR TERM(fodhelper) OR TERM(ftp) OR TERM(pcalua))

Stage 2: regex

| regex parent_process_name="(?i)(forfiles|fodhelper|ftp|pcalua)\.exe"

Stage 3: table

| table _time, host, user parent_*, process, process_*, signature_id

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
parent_process_nameregex_match
  • "(?i)(forfiles|fodhelper|ftp|pcalua).exe" corpus 2 (splunk 2)
field:"parent_process_name" kind:regex_match

Search terms

These SPL tokens match against raw event text.

StageTerm
1"EventCode=1"
1"<EventID>1<"
1forfiles
1fodhelper
1ftp
1pcalua