title: Dllhost Internet Connection
id: cfed2f44-16df-4bf3-833a-79405198b277
status: experimental
description: Detects Dllhost that communicates with public IP addresses
references:
    - https://github.com/Neo23x0/sigma/blob/master/rules/windows/network_connection/sysmon_rundll32_net_connections.yml
author: bartblaze
date: 2020/07/13
modified: 2020/08/24
tags:
    - attack.defense_evasion
    - attack.t1218
    - attack.execution
    - attack.t1559.001  
    - attack.t1175  # an old one  
logsource:
    category: network_connection
    product: windows
detection:
    selection:
        Image: '*\dllhost.exe'
        Initiated: 'true'
    filter:
        DestinationIp:
            - '10.*'
            - '192.168.*'
            - '172.16.*'
            - '172.17.*'
            - '172.18.*'
            - '172.19.*'
            - '172.20.*'
            - '172.21.*'
            - '172.22.*'
            - '172.23.*'
            - '172.24.*'
            - '172.25.*'
            - '172.26.*'
            - '172.27.*'
            - '172.28.*'
            - '172.29.*'
            - '172.30.*'
            - '172.31.*'
            - '127.*'
    condition: selection and not filter
falsepositives:
    - Communication to other corporate systems that use IP addresses from public address spaces
level: medium
