Detection rules › Splunk

Wscript_Cscript Execution (PowerShell)

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

Monitor the execution of wscript or cscript processes as these are commonly utilized by threat actors to run malicious VBScript or JScript code

MITRE ATT&CK coverage

References

Event coverage

Rule body yaml

id: '1029.1032'
title: Wscript_Cscript Execution
description: 'Monitor the execution of wscript or cscript processes as these are commonly
  utilized by threat actors to run malicious VBScript or JScript code Threat Actor
  Association: Actinium/Gamaredon/Primitive Bear, Andariel, Antlion, APT10/menuPass,
  APT28/Fancy Bear, APT29/Nobelium/Cozy Bear, APT31, APT33, APT35, APT37/Chinotto,
  APT43, Blind Eagle/APT-C-36, Carbanak, Evilnum, FIN7, Gamaredon Group/Shuckworm,
  Kimsuky, Mustang Panda (aka. Stately Taurus//Earth Preta/BRONZE PRESIDENT/TA416/RedDelta),
  NewsPenguin, Prophet Spider, TA2541, TA428, TA551, UAC-0057 (GhostWriter), WIRTE,
  Witchetty Software Association: Agent Tesla, Astaroth, Avaddon, Black Basta, BazarLoader,
  Cring, DarkGate, MirrorBlast, NanoCore, PoetRAT, QakBot, RATDispenser, SquirrelWaffle,
  Trickbot, Remcos RAT, WhisperGate, Zloader Atomics T1105 Test #11 Atomics T1059.005
  Test #1 Atomics T1082 Test #9 Atomics T1547.001 Test #5 -- #TrendingThreat #Russia
  #Ukraine'
logic_format: Splunk
logic: ' `get_endpoint_data` `get_endpoint_data_powershell` EventCode=4104 ("cscript.exe"
  OR "WScript.exe") AND (("shell" OR "/cmd") OR ("persist" OR "wait")) OR "cmd.exe"
  OR "net.exe" OR "/c net use" OR "/user:" OR "del" | table _time, host, user dvc,
  dvc_nt_host, event_id, eventtype, host, index, parameters, process, process_id,
  process_name, process_path, shell, signature_id, source, sourcetype, tag, user,
  user_id | bin span=60s | stats values(*) as * by _time, host | where (( like(process,"%cscript.exe%")
  OR like(process,"%WScript.exe%")) AND ((like(process,"%shell%") OR like(process,"%/cmd%"))
  OR (like(process,"%persist%") OR like(process,"%wait%")))) OR (like(process,"%cmd.exe%")
  AND like(process,"%net.exe%") AND like(process,"%/c net use%") AND like(process,"%/user:%")
  AND like(process,"%del%")) '
techniques:
- execution:command and scripting interpreter:visual basic
- execution:command and scripting interpreter:javascript
technique_id:
- T1059.007
- T1059.005
data_category:
- PowerShell logs
references:
- https://secure.anvilogic.com/use_cases?id=AVL_UC1029

Stages and Predicates

Stage 1: search

`get_endpoint_data` `get_endpoint_data_powershell` EventCode=4104 ("cscript.exe" OR "WScript.exe") AND (("shell" OR "/cmd") OR ("persist" OR "wait")) OR "cmd.exe" OR "net.exe" OR "/c net use" OR "/user:" OR "del"

Stage 2: table

| table _time, host, user dvc, dvc_nt_host, event_id, eventtype, host, index, parameters, process, process_id, process_name, process_path, shell, signature_id, source, sourcetype, tag, user, user_id

Stage 3: bucket

| bin span=60s

Stage 4: stats

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

Stage 5: where

| where (( like(process,"%cscript.exe%") OR like(process,"%WScript.exe%")) AND ((like(process,"%shell%") OR like(process,"%/cmd%")) OR (like(process,"%persist%") OR like(process,"%wait%")))) OR (like(process,"%cmd.exe%") AND like(process,"%net.exe%") AND like(process,"%/c net use%") AND like(process,"%/user:%") AND like(process,"%del%"))

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
  • 4104 corpus 268 (splunk 268)
processlike
  • "%/c net use%"
  • "%/cmd%"
  • "%/user:%" corpus 7 (sigma 5, splunk 2)
  • "%WScript.exe%"
  • "%cmd.exe%" corpus 4 (sigma 3, splunk 1)
  • "%cscript.exe%" corpus 2 (sigma 1, splunk 1)
  • "%del%" corpus 3 (sigma 2, splunk 1)
  • "%net.exe%" corpus 3 (sigma 2, splunk 1)
  • "%persist%"
  • "%shell%"
  • "%wait%"

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
1"cscript.exe"
1"WScript.exe"
1"shell"
1"/cmd"
1"persist"
1"wait"
1"cmd.exe"
1"net.exe"
1"/c net use"
1"/user:"
1"del"