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Detection rules › Sigma

Communication To LocaltoNet Tunneling Service Initiated

Status
test
Severity
high
Log source
product windows, category network_connection
Author
Andreas Braathen (mnemonic.io)
Source
github.com/SigmaHQ/sigma

Detects an executable initiating a network connection to "LocaltoNet" tunneling sub-domains. LocaltoNet is a reverse proxy that enables localhost services to be exposed to the Internet. Attackers have been seen to use this service for command-and-control activities to bypass MFA and perimeter controls.

MITRE ATT&CK coverage

TacticTechniques
Command & ControlT1090 Proxy, T1102 Web Service, T1572 Protocol Tunneling

Event coverage

ProviderEventTitle
SysmonEvent ID 3Network connection

Rule body yaml

title: Communication To LocaltoNet Tunneling Service Initiated
id: 3ab65069-d82a-4d44-a759-466661a082d1
status: test
description: |
    Detects an executable initiating a network connection to "LocaltoNet" tunneling sub-domains.
    LocaltoNet is a reverse proxy that enables localhost services to be exposed to the Internet.
    Attackers have been seen to use this service for command-and-control activities to bypass MFA and perimeter controls.
references:
    - https://localtonet.com/documents/supported-tunnels
    - https://cloud.google.com/blog/topics/threat-intelligence/unc3944-targets-saas-applications
author: Andreas Braathen (mnemonic.io)
date: 2024-06-17
tags:
    - attack.command-and-control
    - attack.t1572
    - attack.t1090
    - attack.t1102
logsource:
    category: network_connection
    product: windows
detection:
    selection:
        DestinationHostname|endswith:
            - '.localto.net'
            - '.localtonet.com'
        Initiated: 'true'
    condition: selection
falsepositives:
    - Legitimate use of the LocaltoNet service.
level: high

Stages and Predicates

Stage 0: condition

selection

Stage 1: selection

selection:
    DestinationHostname|endswith:
        - '.localto.net'
        - '.localtonet.com'
    Initiated: 'true'

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
DestinationHostnameends_with
  • .localto.net corpus 2 (sigma 2)
  • .localtonet.com corpus 2 (sigma 2)
Initiatedeq
  • true corpus 50 (sigma 50)