ATT&CK coverage › Technique

Network Sniffing `T1040`

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

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

Provider	Event ID	Title
Sysmon	1	Process creation
Security-Auditing	4688	A new process has been created.
Security-Auditing	4697	A service was installed in the system.
PowerShell	4104	Creating Scriptblock text (MessageNumber of MessageTotal).

Authoring guide

Patterns shared across the 7 rules above: which fields they filter on, what specific values they look for, and what they exclude. Field names are normalized 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 (5 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.

Field	Rules	How	Sample values
`Image`	4	`ends_with` 4	`\netsh.exe`, `\pktmon.exe`, `\windump.exe`, `\tshark.exe`
`OriginalFileName`	3	`eq` 3	`netsh.exe`, `PktMon.exe`
`CommandLine`	3	`match` 3	`wlan`, `s`, `p`, `trace`, `start`
`ScriptBlockText`	1	`match` 1	`Start-NetEventSession`
`ServiceFileName`	1	`match` 1	`npcap`, `ndiscap`, `USBPcap`

Top indicator values (24 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.

Field	Kind	Value	Rules (here)	Corpus reach
`Image`	`ends_with`	`\netsh.exe`	2	16
`OriginalFileName`	`eq`	`netsh.exe`	2	14
`CommandLine`	`match`	`wlan`	1
`CommandLine`	`match`	`s`	1
`CommandLine`	`match`	`=clear`	1
`CommandLine`	`match`	`p`	1	2
`CommandLine`	`match`	`k`	1
`CommandLine`	`match`	`start`	1	6
`CommandLine`	`match`	`trace`	1	2
`OriginalFileName`	`eq`	`PktMon.exe`	1
`Image`	`ends_with`	`\pktmon.exe`	1
`Image`	`ends_with`	`\tshark.exe`	1
`CommandLine`	`match`	`-i`	1	6
`Image`	`ends_with`	`\windump.exe`	1
`ScriptBlockText`	`match`	`Start-NetEventSession`	1
`ServiceFileName`	`match`	`nmnt`	1
`ServiceFileName`	`match`	`npf`	1
`ServiceFileName`	`match`	`npcap`	1
`ServiceFileName`	`match`	`ndiscap`	1
`ServiceFileName`	`match`	`pcap`	1

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

Harvesting Of Wifi Credentials Via Netsh.EXE severity medium, 1 event, 7 indicators, 0 exclusions
New Network Trace Capture Started Via Netsh.EXE severity medium, 1 event, 4 indicators, 0 exclusions
PktMon.EXE Execution severity medium, 1 event, 2 indicators, 0 exclusions
Potential Network Sniffing Activity Using Network Tools severity medium, 2 events, 3 indicators, 0 exclusions
Potential Packet Capture Activity Via Start-NetEventSession - ScriptBlock severity medium, 1 event, 1 indicator, 0 exclusions
Windows Pcap Drivers severity medium, 1 event, 9 indicators, 0 exclusions

Kusto Query Language 1 rule

Powershell Empire Cmdlets Executed in Command Line 1 event, 0 indicators, 0 exclusions

Network Sniffing T1040