System Network Connections Discovery T1049

Events covered

7 catalog events are tagged with this technique by at least one rule.

Authoring guide

Patterns shared across the 33 rules above: which fields they filter on, what specific values they look for, and what they exclude. The catalog normalizes field names across vendors so Sigma's Image, Elastic's process.name, and Splunk's process_name collapse into one row. Each rule contributes at most once per row.

Fields filtered most (27 distinct)

The fields most rules look at when detecting this technique. The How column shows the operators authors use (eq, wildcard, regex_match, match) and how often each appears. Sample values are concrete examples to start from, not an exhaustive list.

Top indicator values (422 distinct)

Specific (field, operator, value) combinations the rules check for, ranked by how many rules under this technique use each one. The Corpus reach column counts how many rules across the entire catalog (any technique) check the same combination. High numbers point to widely-used indicators that are likely noisy on their own; combine them with another condition for useful signal. Blank means the combination is specific to rules under this technique. Click a value to expand the rules under this technique that use it.

Exclusions (132 distinct)

Field/operator/value combinations excluded by rules under this technique (top-level not() clauses), sorted by how many rules exclude each. These are the false-positive paths the community has learned to filter out. A new rule that ignores the high-count entries here will likely fire on the same noisy paths. Click a value to expand the rules under this technique that exclude it.

Rules under this technique

Every rule in the catalog tagged with this technique, grouped by vendor. Click a rule title for its full predicates, exclusions, and indicators.

Sigma 9 rules

• Cisco Discovery
• HackTool - SharpView Execution
• Net.EXE Execution
• Potential Pikabot Discovery Activity
• System Network Connections Discovery - Linux
• System Network Connections Discovery - MacOs
• System Network Connections Discovery Via Net.EXE
• Use Get-NetTCPConnection
• Use Get-NetTCPConnection - PowerShell Module

Elastic 9 rules

• Deprecated - PowerShell Script with Discovery Capabilities
• DNS Enumeration Detected via Defend for Containers
• Enumeration Command Spawned via WMIPrvSE
• Suspicious JetBrains TeamCity Child Process
• Suspicious MS Office Child Process
• Suspicious System Commands Executed by Previously Unknown Executable
• System Network Connections Discovery
• Unusual Linux Network Connection Discovery
• Windows System Network Connections Discovery

Splunk 14 rules

• Common Recon Commands in Short Burst (Sysmon)
• Common Recon Commands in Short Burst (Windows Event Log)
• GetNetTcpconnection with PowerShell
• GetNetTcpconnection with PowerShell Script Block
• Network Connection Discovery With Arp
• Network Connection Discovery With Netstat
• PowerView_SharpView Commands (PowerShell)
• System Network Connections Discovery - Windows (PowerShell)
• System Network Connections Discovery - Windows (Sysmon)
• System Network Connections Discovery - Windows (Windows Event Log)
• Windows Common Abused Cmd Shell Risk Behavior
• Windows Network Connection Discovery Via Net
• Windows Post Exploitation Risk Behavior
• Windows System Network Connections Discovery Netsh

Kusto 1 rule

• Powershell Empire Cmdlets Executed in Command Line