Communication To LocaltoNet Tunneling Service Initiated - Linux

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.

Sigma rule (View on GitHub)

 1title: Communication To LocaltoNet Tunneling Service Initiated - Linux
 2id: c4568f5d-131f-4e78-83d4-45b2da0ec4f1
 3status: experimental
 4description: |
 5    Detects an executable initiating a network connection to "LocaltoNet" tunneling sub-domains.
 6    LocaltoNet is a reverse proxy that enables localhost services to be exposed to the Internet.
 7    Attackers have been seen to use this service for command-and-control activities to bypass MFA and perimeter controls.    
 8references:
 9    - https://localtonet.com/documents/supported-tunnels
10    - https://cloud.google.com/blog/topics/threat-intelligence/unc3944-targets-saas-applications
11author: Andreas Braathen (mnemonic.io)
12date: 2024/06/17
13tags:
14    - attack.command_and_control
15    - attack.t1572
16    - attack.t1090
17    - attack.t1102
18logsource:
19    category: network_connection
20    product: linux
21detection:
22    selection:
23        DestinationHostname|endswith:
24            - '.localto.net'
25            - '.localtonet.com'
26        Initiated: 'true'
27    condition: selection
28falsepositives:
29    - Legitimate use of the LocaltoNet service.
30level: high

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