Detection rules › Splunk

Compressed File Execution (Windows Event Log)

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

This use case looks for the execution of compressed executable

MITRE ATT&CK coverage

References

Event coverage

Rule body yaml

id: '7831.9438'
title: Compressed File Execution
description: 'This use case looks for the execution of compressed executable. Threat
  Actor Association: APT-K-47/Mysterious Elephant, APT10/menuPass, APT36, APT37, Gamaredon
  Group/Shuckworm, Magnat, MuddyWater, InvisiMole, SideWinder, TA402, TA416, TA551,
  TA576, UAC-0057 (GhostWriter), UNC2589 - Software Association: Agent Tesla, ALPHV/Blackcat,
  Bazarloader, Black Basta, Bumblebee Loader, Clop, Conti, DatopLoader, DarkCrystal
  RAT, Emotet, Lockbit, NimbleMamba, PureCrypter, Qakbot/Qbot, Quantum, Remcos RAT,
  Ursnif, Vidar Stealer - Atomics T1027 Test #4 - #TrendingThreat #Russia #Ukraine'
logic_format: Splunk
logic: '`get_endpoint_data` `get_endpoint_data_winevent` (TERM(EventCode=4688) OR
  "<EventID>4688<" OR Type=Process) (".zip" ".exe") | table _time, host, user process,
  process_*, signature_id, parent_* | bin span=1s | stats values(*) as * by _time,
  host | where match(process_path,"(?i)\.zip\x5c.*?\.exe") OR match(parent_process_path,"(?i)\.zip\x5c.*?\.exe") '
techniques:
- defense-evasion:obfuscated files or information
technique_id: 
- T1027
data_category:
- Windows event logs
references:
- https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1027/T1027.md

Stages and Predicates

Stage 1: search

`get_endpoint_data` `get_endpoint_data_winevent` (TERM(EventCode=4688) OR "<EventID>4688<" OR Type=Process) (".zip" ".exe")

Stage 2: table

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

Stage 3: bucket

| bin span=1s

Stage 4: stats

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

Stage 5: where

| where match(process_path,"(?i)\.zip\x5c.*?\.exe") OR match(parent_process_path,"(?i)\.zip\x5c.*?\.exe")

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

FieldKindValues
EventCodeeq
  • 4688 corpus 313 (splunk 283, kusto 30)
parent_process_pathmatch
  • "(?i)\.zip\x5c.*?\.exe"
process_pathmatch
  • "(?i)\.zip\x5c.*?\.exe"

Search terms

Bare-string tokens in the SPL search body. Splunk matches each token against _raw (the untyped raw event text) anywhere it appears, not against a specific field. These don't surface in the Indicators table because they aren't predicates on a known field.

StageTerm
1TERM
1"<EventID>4688<"
1".zip"
1".exe"