Webdial
Overview
Executive Summary
Webdial is a classic example of legacy malware classified as a "Dialer." Highly prevalent during the era of dial-up internet access, Dialers were designed to hijack a computer's modem. Without the user's consent or knowledge, they would disconnect the active internet connection and automatically silently dial an expensive, international, or premium-rate toll number controlled by the attackers, resulting in massive, unexpected telephone bills for the victim.Infection Vector and Technical Capabilities
Webdial was frequently distributed via deceptive websites (often adult content or "free software" portals). Users would be prompted to download a "special access viewer" or a required "codec" to view the site's content, which was actually the malicious dialer executable. Upon execution, the Dialer operated through direct hardware manipulation:- Modem Hijacking: The malware altered the Windows Dial-Up Networking (DUN) configurations. It suppressed the modem's speaker volume (to prevent the user from hearing the dialing tones) and changed the default dial-up connection number.
- Toll Fraud: The dialer would forcefully disconnect the user's local ISP and redial a premium-rate number (often starting with 1-900 or international country codes). The operators of the malware received a cut of the exorbitant per-minute charges levied by the telephone company.
- Persistence: Webdial often placed shortcuts in the Windows Startup folder and modified Registry Run keys to ensure it re-dialed the premium number every time the computer booted.
Threat Assessment
In modern enterprise and consumer environments that utilize broadband (Cable, Fiber, DSL), Webdial and other traditional dialers are entirely obsolete and physically incapable of functioning, as broadband connections do not "dial" phone numbers over analog lines. However, they remain a historically significant example of early financially motivated cybercrime.Historical Remediation
- Connection Termination: The immediate response required physically unplugging the telephone line from the computer's modem to halt the expensive call.
- DUN Reconfiguration: Remediation involved removing the malicious executable and manually reviewing and deleting the unauthorized connections created within the Windows Dial-Up Networking control panel.
- Financial Dispute: Victims often had to undergo a lengthy dispute process with their local telephone provider to have the fraudulent, premium-rate charges removed from their monthly bills.
Known aliases
Threat reports may refer to this family under multiple names:
MITRE ATT&CK Techniques
This family has been observed using the following ATT&CK techniques: T1499 T1132
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_WEBDIAL {
meta:
description = "Detects Webdial (advanced_threat)"
author = "SystemHelpdesk Boilerplate Generator"
date = "2026-07-06"
strings:
$s1 = "webdial" ascii wide nocase
$s2 = "dialer.webdial" ascii wide nocase
$s3 = "trojan.dialer" ascii wide nocase
$s4 = "win32/dialer" ascii wide nocase
condition:
uint16(0) == 0x5a4d and any of them
}Sigma Rule
title: Suspicious Webdial Activity
id: e48b5afd98437613d913d360a36305cf
status: experimental
description: Detects generic indicators of the webdial malware family.
logsource:
category: process_creation
product: windows
detection:
selection:
Image|endswith:
- '\cmd.exe'
- '\powershell.exe'
CommandLine|contains:
- "*webdial*"
- "*dialer.webdial*"
- "*trojan.dialer*"
- "*win32/dialer*"
condition: selection
level: mediumReferences & External Analysis
- Search "webdial" on VirusTotal (External Analysis)
Frequently Asked Questions
How do I remove the Webdial Advanced_Threat from Windows?
Manual removal of Webdial is highly discouraged as it may leave persistence mechanisms intact. We recommend disconnecting the device from the internet and utilizing a professional incident response service or enterprise-grade EDR software to conduct a full forensic sweep.
Is Webdial a virus or a Advanced_Threat?
Webdial is classified as a Advanced_Threat. Unlike traditional viruses that infect files, modern malware like Webdial typically operates as a standalone payload designed to compromise systems, steal data, or deploy secondary stage implants.
What are the main symptoms of a Webdial infection?
Symptoms of Webdial can include unexpected system slowness, unauthorized outbound network traffic to unknown IP addresses, disabled security software, and suspicious background processes running from AppData or Temp directories.
Related Families (Category: advanced_threat)
Explore other malware families in the same category:
Protect Your Network Against Advanced_Threats
Want to prevent Webdial and similar threats from compromising your organization? Read our comprehensive defensive guide: Suspect an Infection? What to do.
Machine-readable
Get this profile as JSON: https://jordan123234-malware-families-explorer.static.hf.space/api/webdial.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.