{
  "family": "3proxy",
  "sample_count": 12,
  "category": "trojan",
  "description": "3Proxy (classified in antivirus detection telemetry under designations including Trojan:Win32/3Proxy, Trojan.Win32.3Proxy, and Win32/3Proxy) is a multi-stage trojan engineered to disguise itself as legitimate software, execute unauthorized commands, and coordinate with external command-and-control infrastructure. Disseminated across enterprise networks and consumer workstations via social engineering, phishing attachments, malicious drive-by downloads, or weaponized software cracks, 3Proxy executes an initial reconnaissance phase upon system ingress. The binary evaluates host privileges, detects active hypervisors and sandbox environments to evade behavioral analysis, and establishes resilient autostart persistence by configuring registry keys under HKCU\\Software\\Microsoft\\Windows\\CurrentVersion\\Run or registering background Windows services. Operational mechanics characteristic of this family include deceptive executable masquerading, registry run key autostart, system telemetry gathering, and remote C2 beaconing. Outbound communication is established with remote threat actor infrastructure to beacon operational status and receive tasking, posing significant security risks to data integrity and host availability.",
  "cta": "Published by the SystemHelpdesk Threat Intelligence Team.",
  "aliases": [
    "Trojan:Win32/3Proxy",
    "Trojan.Win32.3Proxy",
    "Win32/3Proxy"
  ],
  "enrichment_level": "curated_sourced",
  "faq": [
    {
      "@type": "Question",
      "name": "What is Trojan:Win32/3Proxy?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "3Proxy is a trojan threat designed to infiltrate Windows systems and execute unauthorized operations without user consent."
      }
    },
    {
      "@type": "Question",
      "name": "How does 3Proxy compromise target systems?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "It commonly infiltrates systems via phishing emails, trojanized software installers, exploit kits, or unpatched vulnerabilities."
      }
    },
    {
      "@type": "Question",
      "name": "What persistence mechanisms does 3Proxy utilize?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "It typically creates autostart entries in the Windows Registry (HKCU/HKLM Run keys), registers scheduled tasks, or installs hidden background services."
      }
    },
    {
      "@type": "Question",
      "name": "What risks does 3Proxy pose to an enterprise?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "It can lead to credential theft, system manipulation, unauthorized remote access, data loss, or secondary malware delivery."
      }
    },
    {
      "@type": "Question",
      "name": "How can administrators detect and eliminate 3Proxy?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Deploy modern EDR solutions with updated behavioral signatures, isolate infected endpoints, audit autostart persistence entries, and conduct full antimalware scans."
      }
    }
  ],
  "faq_count": 5,
  "mitre_attack": [
    "T1059.003",
    "T1027",
    "T1547.001",
    "T1071.001",
    "T1105"
  ],
  "cisa_advisory": null,
  "last_updated": "2026-10-15",
  "mitre_attack_detail": [
    {
      "id": "T1090.002",
      "name": "Connection Proxy: External Proxy (Abusing the tool for routing)",
      "tactic": "Command and Control"
    },
    {
      "id": "T1543",
      "name": "Create or Modify System Process (Establishing persistence)",
      "tactic": "Persistence"
    },
    {
      "id": "T1105",
      "name": "Ingress Tool Transfer (Downloading 3proxy)",
      "tactic": "Command and Control"
    },
    {
      "id": "T1110.001",
      "name": "Brute Force: Password Guessing",
      "tactic": "Initial Access"
    }
  ],
  "containment_steps": [
    "Isolate the endpoint to immediately sever the proxy connections being routed through the machine.",
    "Identify and terminate the running `3proxy` process, and delete the associated executable and `.cfg` configuration file.",
    "Audit Scheduled Tasks, Registry Run keys, and Services to remove the persistence mechanism that launches the proxy.",
    "Investigate how the attacker gained initial access (e.g., exposed RDP, weak passwords) and remediate the vulnerability to prevent reinfection."
  ],
  "what_to_avoid": [
    "Do not assume 3proxy is inherently malware; check with system administrators to ensure it wasn't installed legitimately for network routing (though rare on standard endpoints).",
    "Avoid relying solely on file deletion, as the attacker may still have the initial access backdoor (like a web shell or compromised credentials) used to install it."
  ],
  "target_industries": [
    "Global / Opportunistic"
  ],
  "motivation": "Opportunistic",
  "threat_actors": [
    "Unknown / Cybercriminal"
  ],
  "target_geographies": [
    "Global"
  ],
  "attack_stage": [
    "execution",
    "persistence"
  ],
  "ecosystem": [
    "windows_pe"
  ],
  "is_emerging": false,
  "sources": [
    {
      "name": "Microsoft Defender Threat Encyclopedia - Trojan:Win32/3Proxy",
      "url": "https://www.microsoft.com/en-us/wdsi/threats/malware-encyclopedia-description?Name=Trojan:Win32/3Proxy"
    },
    {
      "name": "Kaspersky Threat Intelligence - Trojan.Win32.3Proxy",
      "url": "https://threats.kaspersky.com/en/threat/"
    },
    {
      "name": "MITRE ATT&CK - Enterprise Techniques",
      "url": "https://attack.mitre.org/techniques/T1059.003/"
    }
  ],
  "target_platforms": [
    "Windows 11",
    "Windows 10",
    "Windows 7"
  ]
}