Webdial

Overview

Executive Summary

Infection Vector and Technical Capabilities

• 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

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:

• Dialer.Webdial
• Trojan.Dialer
• Win32/Dialer

MITRE ATT&CK Techniques

Observed techniques used by this family, mapped to our technical analysis hubs and the official MITRE ATT&CK framework:

Tactical Mitigations

Based on the techniques used by this family, consider the following defensive strategies:

• T1059.001: Restrict execution of PowerShell. Enforce PowerShell Constrained Language Mode and Script Block Logging.
• T1071.001: Implement web filtering and SSL/TLS inspection to detect malicious command and control (C2) traffic hiding in HTTP/HTTPS.

MITRE D3FEND™ Defensive Countermeasures

Defensive techniques mapped to counter the offensive tradecraft observed in this family (via the MITRE D3FEND matrix):

Tiered Detection Rules (Cisco CAIRN Model)

Modern threat detection requires multi-layered rule engineering. We classify detections into three operational tiers based on signal fidelity:

rule MALWARE_WIN_WEBDIAL_T1_ARTIFACT {
    meta:
        description = "Tier 1 Primitive Artifact: Raw string matches for Webdial"
        tier = "T1 - Primitive Artifact"
        confidence = "Low-Medium (Fast Triage)"
        author = "SystemHelpdesk Threat Research Desk"
        date = "2026-10-14"
    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
}

title: SystemHelpDesk Detection - Webdial (Advanced Threat) Execution & Triage
id: 2cee7486-0cbb-5555-8075-83332fbb8cf4
status: production
description: Detects execution, defense evasion, and persistence behaviors associated
  with the Webdial malware family. Detects proxy execution, reflective DLL loading,
  and remote command injection associated with modular enterprise backdoors.
references:
- https://malware-families-catalog.systemhelpdesk.com/families/webdial
- https://malware-families-catalog.systemhelpdesk.com/defensive/backdoor-rat-protection
- https://malware-families-catalog.systemhelpdesk.com/
author: Ricky Jordan, Lead Threat Intelligence Analyst, SystemHelpDesk MSP
date: '2026-10-14'
modified: '2026-10-14'
tags:
- attack.advanced-threat
- author.ricky-jordan
- source.systemhelpdesk-mfc
- attack.t1499
- attack.t1132
- attack.t1059_001
- attack.t1055
- attack.t1071_001
logsource:
  category: process_creation
  product: windows
detection:
  selection_process:
    Image|endswith:
    - \powershell.exe
    - \cmd.exe
    - \rundll32.exe
    - \regsvr32.exe
    CommandLine|contains:
    - DownloadString
    - IEX(
    - '/s /n /u /i:'
    - sc create
    - start-process
  condition: selection_process
falsepositives:
- Legitimate enterprise administrative scripts during approved change windows
- Authorized IT software deployment utilities and backup management agents
level: high

rule MALWARE_WIN_WEBDIAL_T3_ATTRIBUTION {
    meta:
        description = "Tier 3 Attribution Fingerprint: Heuristic detection for Webdial tradecraft"
        tier = "T3 - Attribution Fingerprint"
        confidence = "High (Confirmed Family Signature)"
        author = "SystemHelpdesk Threat Research Desk"
        date = "2026-10-14"
    strings:
        // Core family identifier & heuristic payload signatures
        $attrib_str = "webdial" ascii wide nocase
        $pe_magic = "MZ" ascii
        $net_marker = "http" ascii nocase
    condition:
        uint16(0) == 0x5a4d and ($attrib_str and $net_marker) and filesize < 15MB
}

Containment & Response Steps

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

1. Enforce forensic network isolation on all suspected endpoints while maintaining an out-of-band telemetry conduit to capture live Webdial adversary activity.
2. Perform full memory dumps across identified staging nodes to extract memory-only implants, kernel rootkit hooks, and decrypted Webdial C2 infrastructure IP/domain lists.
3. Review Active Directory domain controller authentication logs for anomalous Kerberos ticket requests (Pass-the-Ticket, Golden Ticket) and unauthorized DCSync operations associated with Webdial.
4. Block all confirmed C2 domains, dynamic DNS endpoints, and proxy IP addresses across perimeter firewalls, proxies, and DNS security gateways.
5. Conduct an enterprise-wide sweep across surrounding subnets for secondary webshells, WMI event subscriptions, or remote execution tooling left behind by Webdial operators.

What to Avoid

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

1. Do not assume the incident is resolved simply because an antivirus tool removed the initial Webdial dropper; always verify that secondary payloads and persistence hooks have been eradicated.
2. Avoid logging in with Domain Admin or privileged credentials on a machine suspected of running Webdial until memory triage is complete.
3. Do not delay host isolation; automated lateral movement and credential dumping can occur within minutes of initial execution.

References & External Analysis

• Search "webdial" on VirusTotal (External Analysis)
• Search "webdial" on Any.Run (Sandbox Sandbox)
• Search "webdial" on MalwareBazaar (Malware Samples)

Frequently Asked Questions

Related Threats (Category: Advanced Threat)

Explore other documented threats in the same operational category:

• Mediafinder
• Sogou
• Turla
• Safeterra
• Libsam
• Rontokbr
• Softomate
• Mobogenie

Machine-readable

Get this profile as JSON: https://malware-families-catalog.systemhelpdesk.com/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.