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Detection rules › Sigma

Potential Packet Capture Activity Via Start-NetEventSession - ScriptBlock

Status
test
Severity
medium
Log source
product windows, category ps_script
Author
frack113
Source
github.com/SigmaHQ/sigma

Detects the execution of powershell scripts with calls to the "Start-NetEventSession" cmdlet. Which allows an attacker to start event and packet capture for a network event session. Adversaries may attempt to capture network to gather information over the course of an operation. Data captured via this technique may include user credentials, especially those sent over an insecure, unencrypted protocol.

MITRE ATT&CK coverage

TacticTechniques
Credential AccessT1040 Network Sniffing
DiscoveryT1040 Network Sniffing

Event coverage

ProviderEventTitle
PowerShellEvent ID 4104Creating Scriptblock text (MessageNumber of MessageTotal).

Rule body yaml

title: Potential Packet Capture Activity Via Start-NetEventSession - ScriptBlock
id: da34e323-1e65-42db-83be-a6725ac2caa3
status: test
description: |
    Detects the execution of powershell scripts with calls to the "Start-NetEventSession" cmdlet. Which allows an attacker to start event and packet capture for a network event session.
    Adversaries may attempt to capture network to gather information over the course of an operation.
    Data captured via this technique may include user credentials, especially those sent over an insecure, unencrypted protocol.
references:
    - https://github.com/redcanaryco/atomic-red-team/blob/5f866ca4517e837c4ea576e7309d0891e78080a8/atomics/T1040/T1040.md#atomic-test-16---powershell-network-sniffing
    - https://github.com/0xsyr0/Awesome-Cybersecurity-Handbooks/blob/7b8935fe4c82cb64d61343de1a8b2e38dd968534/handbooks/10_post_exploitation.md
    - https://github.com/forgottentq/powershell/blob/9e616363d497143dc955c4fdce68e5c18d28a6cb/captureWindows-Endpoint.ps1#L13
author: frack113
date: 2024-05-12
tags:
    - attack.credential-access
    - attack.discovery
    - attack.t1040
logsource:
    product: windows
    category: ps_script
    definition: 'Requirements: Script Block Logging must be enabled'
detection:
    selection:
        ScriptBlockText|contains: 'Start-NetEventSession'
    condition: selection
falsepositives:
    - Legitimate network diagnostic scripts.
level: medium

Stages and Predicates

Stage 0: condition

selection

Stage 1: selection

selection:
    ScriptBlockText|contains: 'Start-NetEventSession'

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.

FieldKindValues
ScriptBlockTextmatch
  • Start-NetEventSession