Sigma rule: Outbound Network Connection Initiated By Microsoft Dialer

Rule

Title

Outbound Network Connection Initiated By Microsoft Dialer

Status

test

Level

high

Author

CertainlyP

Date

2024-04-26

File

rules/windows/network_connection/net_connection_win_dialer_initiated_connection.yml

Commit

ccbb0369507f796db0b0ae6854c8a2be471b9d84

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This is an outdated process in the current conext of it's usage and is a common target for info stealers for process injection, and is used to make C2 connections, common example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"

Log source

product

windows

category

network_connection

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 (as the rule lists them)

• 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.

Tags

• attack.execution
• attack.command-and-control
• attack.t1071.001

MITRE ATT&CK ids this rule names

• T1071.001

References

• https://tria.ge/240301-rk34sagf5x/behavioral2
• https://app.any.run/tasks/6720b85b-9c53-4a12-b1dc-73052a78477d
• https://research.checkpoint.com/2023/rhadamanthys-v0-5-0-a-deep-dive-into-the-stealers-components/
• https://strontic.github.io/xcyclopedia/library/dialer.exe-0B69655F912619756C704A0BF716B61F.html

Read on 2026-11-03T00:58:21.399Z under licence sigma-drl-1.1@d5f4c36a from https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules/windows/network_connection/net_connection_win_dialer_initiated_connection.yml