Detectionhightest

Outbound Network Connection Initiated By Microsoft Dialer

Detects outbound network connection initiated by Microsoft Dialer. The Microsoft Dialer, also known as Phone Dialer, is a built-in utility application included in various versions of the Microsoft Windows operating system. Its primary function is to provide users with a graphical interface for managing phone calls via a modem or a phone line connected to the computer. This is an outdated process in the current conext of it's usage and is a common target for info stealers for process injection, and is used to make C2 connections, common example is "Rhadamanthys"

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Launch
CertainlyPCreated Fri Apr 2637e4024a-6c80-4d8f-b95d-2e7e94f3a8d1windows
Log Source
WindowsNetwork Connection
ProductWindows← raw: windows
CategoryNetwork Connection← raw: network_connection

Events for outbound and inbound network connections including DNS resolution.

Detection Logic
Detection Logic2 selectors
detection:
    selection:
        Image|endswith: ':\Windows\System32\dialer.exe'
        Initiated: 'true'
    filter_main_local_ranges:
        DestinationIp|cidr:
            - '127.0.0.0/8'
            - '10.0.0.0/8'
            - '172.16.0.0/12'
            - '192.168.0.0/16'
            - '169.254.0.0/16'
            - '::1/128'  # IPv6 loopback
            - 'fe80::/10'  # IPv6 link-local addresses
            - 'fc00::/7'  # IPv6 private addresses
    condition: selection and not 1 of filter_main_*
False Positives

In Modern Windows systems, unable to see legitimate usage of this process, However, if an organization has legitimate purpose for this there can be false positives.

Rule Metadata
Rule ID
37e4024a-6c80-4d8f-b95d-2e7e94f3a8d1
Status
test
Level
high
Type
Detection
Created
Fri Apr 26
Path
rules/windows/network_connection/net_connection_win_dialer_initiated_connection.yml
Raw Tags
attack.executionattack.command-and-controlattack.t1071.001
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