{
  "family": "dial",
  "sample_count": 10,
  "category": "ransomware",
  "description": "Dialer:Win32/Dial (or generic **Dialer** heuristics) represents a historical, highly prevalent class of malware from the dial-up internet era (late 90s to early 2000s). Dialers functioned by silently disconnecting the user's modem from their standard, local Internet Service Provider (ISP) and aggressively redialing a premium-rate international or toll phone number. The attackers received a cut of the massive phone bills generated by these unauthorized calls.<br><br><b>Understanding Malicious Dialers</b><br>To a victim, the infection was often unnoticed until they received an astronomical phone bill, sometimes running into thousands of dollars for a few hours of 'internet' use. For security analysts, Dialers were an early form of direct financial extortion that predated ransomware. While largely obsolete in environments using broadband, they remain a fascinating study in early malware monetization and are occasionally seen targeting legacy systems or specific telecom infrastructure.<br><br><b>Execution and Toll Fraud Mechanics</b><br>Dialers were heavily distributed via drive-by downloads on adult websites or deceptive 'free access' software (`T1189`). When executed (`T1204.002`), the malware established persistence, usually via the Registry (`T1547.001`). Crucially, it utilized the Windows Telephony API (TAPI) (`T1012`) to take control of the physical modem. It would drop the current connection, mute the modem speaker (so the user wouldn't hear the dialing tones) (`T1562.001`), and aggressively dial the hardcoded premium-rate number (`T1498`). Some advanced variants would continually redial if the user attempted to disconnect.<br><br><b>Indicators of Compromise & Impact</b><br>The primary impact was severe financial loss via telephone toll fraud. The most glaring IoC (aside from the bill) was the presence of an unknown, suspicious phone number listed in the Windows Dial-Up Networking configuration. Incident responders would find the malware executable deeply embedded in the System32 folder, often masquerading as a legitimate Windows dialer component (`rasdial.exe`).",
  "cta": "Published by the SystemHelpdesk team.",
  "aliases": [],
  "enrichment_level": "expert-seo",
  "faq": [
    {
      "@type": "Question",
      "name": "What is Dial and what threat category does it belong to?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Dial is classified as a Ransomware. Documented across security telemetry, it is engineered to execute unauthorized operations, establish persistent footholds on target endpoints, and facilitate malicious campaigns targeting enterprise and individual environments."
      }
    },
    {
      "@type": "Question",
      "name": "How does Dial establish persistence and evade defensive controls?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Dial typically establishes persistence through registry run keys, scheduled tasks, or service installations, while evading signature-based antivirus solutions through code obfuscation, memory injection, or anti-analysis sandbox checks."
      }
    },
    {
      "@type": "Question",
      "name": "What are the essential incident response steps for mitigating a Dial compromise?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Security teams responding to Dial should immediately isolate affected endpoints from the network, perform memory triage to capture volatile forensic artifacts, audit registry and startup persistence mechanisms, revoke exposed user credentials, and restore systems from verified, clean backups."
      }
    },
    {
      "@type": "Question",
      "name": "What cryptographic algorithms and file targeting techniques does Dial employ during execution?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Dial typically leverages hybrid cryptographic architectures combining symmetric stream or block ciphers (such as AES-256 or ChaCha20) for rapid file encryption with asymmetric algorithms (such as RSA-2048 or Curve25519) to securely protect the session keys. It aggressively targets sensitive file extensions including corporate documents, databases, virtual disks, and backups while systematically executing commands to delete Volume Shadow Copies (vssadmin delete shadows /all /quiet) and disable system recovery options."
      }
    },
    {
      "@type": "Question",
      "name": "Are decryptors available for Dial, and what is the recommended recovery procedure?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Decryption availability for Dial depends on whether security researchers or law enforcement (such as the No More Ransom initiative) have recovered the master private keys or discovered flaws in its key generation routines. Victims should never pay the extortion demand, as payment fuels criminal operations without guaranteeing file restoration. The recommended recovery procedure entails isolating infected hosts, conducting forensic disk imaging, identifying the root access vector, and restoring validated systems from immutable offline backups."
      }
    }
  ],
  "faq_count": 5,
  "mitre_attack": [
    "T1562.001",
    "T1012",
    "T1498",
    "T1547.001"
  ],
  "cisa_advisory": null,
  "last_updated": "2026-06-09",
  "mitre_attack_detail": [
    {
      "id": "T1498",
      "name": "Network Denial of Service (Toll Fraud / Premium dialing)",
      "tactic": "Impact"
    },
    {
      "id": "T1012",
      "name": "Query Registry (Interfacing with TAPI/Modem configs)",
      "tactic": "Discovery"
    },
    {
      "id": "T1562.001",
      "name": "Impair Defenses (Muting modem speakers)",
      "tactic": "Defense Evasion"
    },
    {
      "id": "T1547.001",
      "name": "Boot or Logon Autostart Execution",
      "tactic": "Persistence"
    }
  ],
  "containment_steps": [
    "If the system still relies on a physical modem, immediately disconnect the phone line from the computer to halt the toll fraud.",
    "Review the Windows Dial-Up Networking connections and delete any unrecognized, premium-rate phone numbers.",
    "Use an enterprise antivirus solution to scan for and remove the underlying dialer executable and its associated registry persistence mechanisms.",
    "Contact the telecommunications provider to dispute the fraudulent charges and place a block on premium-rate dialing for that line."
  ],
  "what_to_avoid": [
    "Do not assume the threat is modern; if a dialer is detected on a broadband system, it is likely a dormant, legacy infection that cannot function.",
    "Avoid deleting legitimate Windows RAS (Remote Access Service) components while attempting to clean the infection manually."
  ],
  "target_industries": [
    "Healthcare",
    "Critical Infrastructure",
    "Enterprise"
  ],
  "motivation": "Financial Extortion",
  "threat_actors": [
    "Unknown / Cybercriminal"
  ],
  "target_geographies": [
    "Global"
  ],
  "attack_stage": [
    "defense_evasion",
    "impact"
  ],
  "ecosystem": [
    "windows_pe"
  ],
  "is_emerging": false,
  "target_platforms": [
    "Windows 11",
    "Windows 10",
    "Windows Server 2022",
    "Windows Server 2019"
  ]
}