{
  "family": "arcdoor",
  "sample_count": 4,
  "category": "backdoor",
  "description": "Arcdoor (classified in antivirus detection telemetry under designations including Backdoor:Win32/Arcdoor, Backdoor.Win32.Arcdoor, and Win32/Arcdoor) is a interactive remote access trojan and backdoor providing remote threat actors with unauthorized terminal control, file manipulation, and surveillance. Disseminated across enterprise networks and consumer workstations via social engineering, phishing attachments, malicious drive-by downloads, or weaponized software cracks, Arcdoor 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 reverse shell connections, process hollowing, privilege escalation, and lateral movement reconnaissance. 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": [
    "Backdoor:Win32/Arcdoor",
    "Backdoor.Win32.Arcdoor",
    "Win32/Arcdoor"
  ],
  "enrichment_level": "curated_sourced",
  "faq": [
    {
      "@type": "Question",
      "name": "What is Backdoor:Win32/Arcdoor?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Arcdoor is a backdoor threat designed to infiltrate Windows systems and execute unauthorized operations without user consent."
      }
    },
    {
      "@type": "Question",
      "name": "How does Arcdoor 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 Arcdoor 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 Arcdoor 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 Arcdoor?",
      "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",
    "T1055",
    "T1573",
    "T1547.001",
    "T1070"
  ],
  "cisa_advisory": null,
  "last_updated": "2026-10-16",
  "mitre_attack_detail": [
    {
      "id": "T1059.003",
      "name": "Command and Scripting Interpreter: Windows Command Shell",
      "tactic": "Execution"
    },
    {
      "id": "T1071.001",
      "name": "Application Layer Protocol: Web Protocols (C2 Communication)",
      "tactic": "Command and Control"
    },
    {
      "id": "T1055",
      "name": "Process Injection (Hiding in legitimate processes)",
      "tactic": "Defense Evasion"
    },
    {
      "id": "T1543.003",
      "name": "Create or Modify System Process: Windows Service",
      "tactic": "Persistence"
    }
  ],
  "containment_steps": [
    "Isolate the endpoint from the network immediately to sever the active attacker connection and prevent lateral movement.",
    "Analyze the memory of the running `svchost.exe` processes to identify the injected Arcdoor module and extract the C2 IP addresses/domains.",
    "Block the identified C2 infrastructure at the corporate firewall and proxy, and hunt across the network for other endpoints communicating with those IPs.",
    "Assume all credentials present on the infected machine have been compromised and initiate enterprise-wide password resets."
  ],
  "what_to_avoid": [
    "Do not simply run a file-based AV scan and leave the machine online; backdoors often update themselves or deploy rootkits, requiring a full wipe and reimage.",
    "Avoid investigating the endpoint on the live network, as the attacker may notice the investigation and deploy destructive wipers to cover their tracks."
  ],
  "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 - Backdoor:Win32/Arcdoor",
      "url": "https://www.microsoft.com/en-us/wdsi/threats/malware-encyclopedia-description?Name=Backdoor:Win32/Arcdoor"
    },
    {
      "name": "Kaspersky Threat Intelligence - Backdoor.Win32.Arcdoor",
      "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 Server 2022",
    "Windows Server 2019"
  ]
}