Detection rules › Sigma

Ngrok Usage with Remote Desktop Service

Status
test
Severity
high
Log source
product windows, service terminalservices-localsessionmanager
Author
Florian Roth (Nextron Systems)
Source
github.com/SigmaHQ/sigma

Detects cases in which ngrok, a reverse proxy tool, forwards events to the local RDP port, which could be a sign of malicious behaviour

MITRE ATT&CK coverage

TacticTechniques
Command & ControlT1090 Proxy

Event coverage

Rule body yaml

title: Ngrok Usage with Remote Desktop Service
id: 64d51a51-32a6-49f0-9f3d-17e34d640272
status: test
description: Detects cases in which ngrok, a reverse proxy tool, forwards events to the local RDP port, which could be a sign of malicious behaviour
references:
    - https://twitter.com/tekdefense/status/1519711183162556416?s=12&t=OTsHCBkQOTNs1k3USz65Zg
    - https://ngrok.com/
author: Florian Roth (Nextron Systems)
date: 2022-04-29
tags:
    - attack.command-and-control
    - attack.t1090
logsource:
    product: windows
    service: terminalservices-localsessionmanager
detection:
    selection:
        EventID: 21
        Address|contains: '16777216'
    condition: selection
falsepositives:
    - Unknown
level: high

Stages and Predicates

Stage 0: condition

selection

Stage 1: selection

selection:
    EventID: 21
    Address|contains: '16777216'

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
Addressmatch
  • 16777216