Detection rules › Splunk
System Network Connections Discovery - Windows (PowerShell)
Adversaries may attempt to get a listing of network connections to or from the compromised system they are currently accessing or from remote systems by querying for information over the network
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Discovery | T1049 System Network Connections Discovery |
References
Event coverage
| Provider | Event | Title |
|---|---|---|
| PowerShell | Event ID 4103 | Payload Context: ContextInfo User Data: UserData. |
| PowerShell | Event ID 4104 | Creating Scriptblock text (MessageNumber of MessageTotal). |
Rule body yaml
id: '16272.24664'
title: System Network Connections Discovery - Windows
description: 'Adversaries may attempt to get a listing of network connections to or
from the compromised system they are currently accessing or from remote systems
by querying for information over the network. -- Threat Actor Association: Alloy
Taurus/Gallium, Volt Typhoon -- Atomics T1049 Test #1 Atomics T1049 Test #2'
logic_format: Splunk
logic: '`get_endpoint_data` `get_endpoint_data_powershell` (TERM(EventCode=4103) OR
"<EventID>4103<" OR TERM(EventCode=4104) OR "<EventID>4104<") "netstat" OR ("net"
("use" or "sessions")) OR TERM(Get-NetTCPConnection) | regex process="(?i)netstat(\.exe)?|net(\.exe)?\s+(use|sessions)|Get-TCPConnection"
| table _time, host, user process, process_* | bin span=1s | stats values(*) as
* by _time, host '
techniques:
- discovery:system network connections discovery
technique_id:
- T1049
data_category:
- PowerShell logs
references:
- https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1049/T1049.md#atomic-test-1---system-network-connections-discovery
- https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1049/T1049.md#atomic-test-2---system-network-connections-discovery-with-powershell
Stages and Predicates
Stage 1: search
`get_endpoint_data` `get_endpoint_data_powershell` (TERM(EventCode=4103) OR "<EventID>4103<" OR TERM(EventCode=4104) OR "<EventID>4104<") "netstat" OR ("net" ("use" or "sessions")) OR TERM(Get-NetTCPConnection)
Stage 2: regex
| regex process="(?i)netstat(\.exe)?|net(\.exe)?\s+(use|sessions)|Get-TCPConnection"
Stage 3: table
| table _time, host, user process, 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>4103<" |
| 1 | TERM |
| 1 | "<EventID>4104<" |
| 1 | "netstat" |
| 1 | "net" |
| 1 | "use" |
| 1 | "sessions" |
| 1 | "Get-NetTCPConnection" |