Egroupdial

Overview

Dialer:Win32/Egroupdial represents a legacy classification of malware that was highly prevalent during the era of dial-up internet modems. It is designed to commit financial fraud by silently disconnecting a user's modem from their standard Internet Service Provider (ISP) and reconnecting it to a premium-rate international or adult-service phone number, generating massive, unauthorized charges on the victim's phone bill.

Understanding Dialer Malware
To an end-user in the early 2000s, an Egroupdial infection was often unnoticeable until they received a phone bill for thousands of dollars in international calls. While modern broadband (cable/fiber) is entirely immune to dialers because they do not use phone lines to route traffic, Dialers remain a critical historical case study in automated financial extortion and telecommunications fraud.

Execution and Dialing Mechanics
Egroupdial was typically distributed via deceptive 'free access' links on adult websites or bundled with pirated software (`T1189`). Upon execution (`T1204.002`), the malware establishes persistence and immediately interfaces with the Windows Telephony Application Programming Interface (TAPI) (`T1562.001`). It suppresses the modem speaker volume so the user cannot hear the dialing tones (`T1562.001`). It then terminates the active dial-up connection and initiates a new PPP (Point-to-Point Protocol) connection to a hardcoded, premium-rate phone number controlled by the malware authors (`T1498`), keeping the connection open as long as possible to maximize revenue.

Indicators of Compromise & Impact
The primary impact is direct, massive financial loss for the user via their telecommunications provider. Technical IoCs on legacy systems included the creation of new, unauthorized Dial-Up Networking (DUN) profiles in the Windows Network Connections panel. Behavioral IoCs included the modem spontaneously disconnecting and reconnecting, and the modem speaker being permanently muted.

MITRE ATT&CK Techniques

Observed techniques used by this family, mapped to the MITRE ATT&CK framework:

Generated Detections (Boilerplate)

These YARA and Sigma rules are auto-generated based on the family name and aliases. They must be heavily tuned before deployment in a production environment.

YARA Rule

rule MALWARE_WIN_EGROUPDIAL {
    meta:
        description = "Detects Egroupdial (advanced_threat)"
        author = "SystemHelpdesk Boilerplate Generator"
        date = "2026-07-06"
    strings:
        $s1 = "egroupdial" ascii wide nocase
    condition:
        uint16(0) == 0x5a4d and any of them
}

Sigma Rule

title: Suspicious Egroupdial Activity
id: b7edb6c4cffde4fd4a66a43a1ed8f3df
status: experimental
description: Detects generic indicators of the egroupdial malware family.
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        Image|endswith:
            - '\cmd.exe'
            - '\powershell.exe'
        CommandLine|contains:
            - "*egroupdial*"
    condition: selection
level: medium

Containment & Response Steps

Ordered checklist for responders. Adapt to your environment and engage professional support for active incidents.

1. If analyzing a legacy system, physically unplug the phone line from the modem immediately to halt the fraudulent charges.
2. Delete any unknown Dial-Up Networking (DUN) connection profiles found in the Network Connections control panel.
3. Use standard antivirus to remove the Egroupdial executable and its persistence mechanisms.
4. Contact the telecommunications provider to report the fraud and request a block on all international or premium-rate dialing from that landline.

What to Avoid

Common mistakes during response to this family that can destroy evidence, spread the infection, or worsen recovery.

1. Do not assume modern endpoints are vulnerable; this threat requires a physical analog modem connected to a landline to function.
2. Avoid paying the phone bill without first disputing the charges as fraud with the telecommunications carrier.

References & External Analysis

• Search "egroupdial" on VirusTotal (External Analysis)

Frequently Asked Questions

Related Families (Category: advanced_threat)

Explore other malware families in the same category:

• Nspm
• Wmfap
• Softomate
• Toggle
• Gotango

Machine-readable

Get this profile as JSON: https://jordan123234-malware-families-explorer.static.hf.space/api/egroupdial.json

Ecosystem & Interactive Environments

This profile is part of the Malware Families Catalog, a public dataset of 2,899 malware families. The catalog is also published across our ecosystem: Hugging Face, Kaggle, Zenodo, Replit, StackBlitz, CodeSandbox, and CodePen.