Detection rules › Splunk
Suspicious Executable by CMD.exe (Sysmon)
Detect when an executable has been launched by cmd.exe. Such as spawning powershell.exe, cscript rundll32 and similar processes being a child process of cmd
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Execution |
References
Telemetry coverage
| Provider | Record / event type |
|---|---|
| Sysmon | Event ID 1: Process creation |
Rule body
id: '8823.11629'
title: Suspicious Executable by CMD.exe
description: 'Detect when an executable has been launched by cmd.exe. Such as spawning
powershell.exe, cscript rundll32 and similar processes being a child process of
cmd. -- Threat Actor Association: APT28 (aka.Fancy Bear, Fighting Ursa, Forest Blizzard,
Pawn Storm, TA422, STRONTIUM), APT34/OilRig, APT43, FIN8, Flax Typhoon, REvil, WinterVivern/UAC-0114
- Software Association: Alchimist, AvosLocker, Black Basta, MagicRAT, Rhysida'
logic_format: Splunk
logic: '`get_endpoint_data` `get_endpoint_data_sysmon` (TERM(EventCode=1) OR "<EventID>1<")
"cmd.exe" ("powershell.exe" OR "services.exe" OR "dllhost.exe" OR "rundll32.exe"
OR "cscript.exe" OR "regsvr32.exe") | regex parent_process_name="(?i)(cmd\.exe)"
| regex process_path="(?i)((powershell)|(services)|(dllhost)|(rundll32)|(cscript)|(regsvr32))\.exe"
| table _time, host, user event_id, parent_*, process_*, process, signature_id,
src_*, dest_* | bin span=1s | stats values(*) as * by _time, host | where isnotnull(user) '
techniques:
- execution:command and scripting interpreter
technique_id:
- T1059
data_category:
- Windows Sysmon
references:
- https://secure.anvilogic.com/use_cases?id=AVL_UC1041#more_info
Stages and Predicates
Stage 1: search
`get_endpoint_data` `get_endpoint_data_sysmon` (TERM(EventCode=1) OR "<EventID>1<") "cmd.exe" ("powershell.exe" OR "services.exe" OR "dllhost.exe" OR "rundll32.exe" OR "cscript.exe" OR "regsvr32.exe")
Stage 2: regex
| regex parent_process_name="(?i)(cmd\.exe)"
Stage 3: regex
| regex process_path="(?i)((powershell)|(services)|(dllhost)|(rundll32)|(cscript)|(regsvr32))\.exe"
Stage 4: table
| table _time, host, user event_id, parent_*, process_*, process, signature_id, src_*, dest_*
Stage 5: bucket
| bin span=1s
Stage 6: stats
| stats values(*) as * by _time, host
Stage 7: where
| where isnotnull(user)
Indicators
These rows show field, operator, and value matches.
| Field | Kind | Values | Search |
|---|---|---|---|
EventCode | eq |
| field:"EventID" kind:eq value:"1" |
parent_process_name | regex_match |
| field:"parent_process_name" kind:regex_match |
process_path | regex_match |
| field:"process_name" kind:regex_match |
user | is_not_null | field:"user" kind:is_not_null |
Search terms
These SPL tokens match against raw event text.
| Stage | Term |
|---|---|
| 1 | "<EventID>1<" |
| 1 | "cmd.exe" |
| 1 | "powershell.exe" |
| 1 | "services.exe" |
| 1 | "dllhost.exe" |
| 1 | "rundll32.exe" |
| 1 | "cscript.exe" |
| 1 | "regsvr32.exe" |