Detection rules › Splunk
NMAP Execution (PowerShell)
Adversaries may attempt to get a listing of other systems by IP address, hostname, or other logical identifier on a network that may be used for Lateral Movement from the current system. This use case looks for executions of nmap that have been passed an IPv4 Address
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Discovery | T1018 Remote System Discovery |
References
Event coverage
| Provider | Event | Title |
|---|---|---|
| PowerShell | Event ID 4104 | Creating Scriptblock text (MessageNumber of MessageTotal). |
Rule body yaml
id: '6127.6611'
title: NMAP Execution
description: 'Adversaries may attempt to get a listing of other systems by IP address,
hostname, or other logical identifier on a network that may be used for Lateral
Movement from the current system. This use case looks for executions of nmap that
have been passed an IPv4 Address. -- Threat Actor Association: Alloy Taurus/Gallium'
logic_format: Splunk
logic: '`get_endpoint_data` `get_endpoint_data_powershell` (TERM(EventCode=4104) OR
TERM(<EventID>4104<)) (TERM(nmap) OR "nmap.exe") | regex process="(?i)nmap(\.exe)?\"?\s+.+?(\d{1,3}\.){3}\d{1,3}"
| table _time, host, user, signature_id, process, process_*, parent_process_* |
bin span=1s | stats values(*) as * by _time, host '
techniques:
- discovery:remote system discovery
technique_id:
- T1018
data_category:
- PowerShell logs
- Process command-line parameters
references:
- https://www.group-ib.com/resources/threat-research/silence_moving-into-the-darkside.pdf
Stages and Predicates
Stage 1: search
`get_endpoint_data` `get_endpoint_data_powershell` (TERM(EventCode=4104) OR TERM(<EventID>4104<)) (TERM(nmap) OR "nmap.exe")
Stage 2: regex
| regex process="(?i)nmap(\.exe)?\"?\s+.+?(\d{1,3}\.){3}\d{1,3}"
Stage 3: table
| table _time, host, user, signature_id, process, process_*, parent_process_*
Stage 4: bucket
| bin span=1s
Stage 5: stats
| stats values(*) as * by _time, host
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.
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.
| Stage | Term |
|---|---|
| 1 | TERM |
| 1 | "<EventID>4104<" |
| 1 | TERM |
| 1 | nmap |
| 1 | "nmap.exe" |