System Network Connections Discovery T1049
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.
Events covered
5 catalog events are tagged with this technique by at least one rule.
| Provider | Event | Title |
|---|---|---|
| Sysmon | Event ID 1 | Process creation |
| Security-Auditing | Event ID 4688 | A new process has been created. |
| PowerShell | Event ID 4103 | Payload Context: ContextInfo User Data: UserData. |
| PowerShell | Event ID 4104 | Creating Scriptblock text (MessageNumber of MessageTotal). |
| PowerShell | Event ID 400 | Event ID 400 |
Authoring guide
Patterns shared across the 22 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 (18 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 (213 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 (23 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 6 rules
- HackTool - SharpView Execution
- Net.EXE Execution
- Potential Pikabot Discovery Activity
- System Network Connections Discovery Via Net.EXE
- Use Get-NetTCPConnection
- Use Get-NetTCPConnection - PowerShell Module
Elastic 3 rules
- Enumeration Command Spawned via WMIPrvSE
- Suspicious JetBrains TeamCity Child Process
- Suspicious MS Office Child Process
Splunk 12 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 Network Connection Discovery Via Net
- Windows System Network Connections Discovery Netsh