Network Sniffing T1040
Tactics: Credential Access, Discovery
Adversaries may passively sniff network traffic to capture information about an environment, including authentication material passed over the network. Network sniffing refers to using the network interface on a system to monitor or capture information sent over a wired or wireless connection. An adversary may place a network interface into promiscuous mode to passively access data in transit over the network, or use span ports to capture a larger amount of data.
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. |
| Security-Auditing | Event ID 4697 | A service was installed in the system. |
| ESF | exec | Process Execution (Notify) |
| PowerShell | Event ID 4104 | Creating Scriptblock text (MessageNumber of MessageTotal). |
Authoring guide
Patterns shared across the 24 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 (41 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 (170 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 (25 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 11 rules
- Cisco Sniffing
- Harvesting Of Wifi Credentials Via Netsh.EXE
- Network Sniffing - Linux
- Network Sniffing - MacOs
- New Network Trace Capture Started Via Netsh.EXE
- PktMon.EXE Execution
- Potential Network Sniffing Activity Using Network Tools
- Potential Packet Capture Activity Via Start-NetEventSession - ScriptBlock
- Windows native Pktmon sniffer abuse
- Windows Pcap Drivers
- Windows traffic capture abuse
Elastic 5 rules
- AWS EC2 Full Network Packet Capture Detected
- Azure VNet Full Network Packet Capture Enabled
- Network Traffic Capture via CAP_NET_RAW
- Suspicious Network Tool Launch Detected via Defend for Containers
- Suspicious Network Tool Launched Inside A Container
Splunk 2 rules
Kusto 3 rules
- Azure secure score PW age policy new
- Powershell Empire Cmdlets Executed in Command Line
- Zoom E2E Encryption Disabled