{
  "family": "adduser",
  "sample_count": 4,
  "category": "backdoor",
  "description": "Adduser (classified in antivirus detection telemetry under designations including Backdoor:Win32/Adduser, Backdoor.Win32.Adduser, and Win32/Adduser) 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, Adduser 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/Adduser",
    "Backdoor.Win32.Adduser",
    "Win32/Adduser"
  ],
  "enrichment_level": "curated_sourced",
  "faq": [
    {
      "@type": "Question",
      "name": "What is Backdoor:Win32/Adduser?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Adduser is a backdoor threat designed to infiltrate Windows systems and execute unauthorized operations without user consent."
      }
    },
    {
      "@type": "Question",
      "name": "How does Adduser 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 Adduser 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 Adduser 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 Adduser?",
      "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": "2026-10-15",
  "mitre_attack_detail": [
    {
      "id": "T1136.001",
      "name": "Create Account: Local Account (net user /add)",
      "tactic": "Persistence"
    },
    {
      "id": "T1136.002",
      "name": "Create Account: Domain Account",
      "tactic": "Persistence"
    },
    {
      "id": "T1059.003",
      "name": "Command and Scripting Interpreter: Windows Command Shell",
      "tactic": "Execution"
    }
  ],
  "containment_steps": [
    "Immediately disable (do not delete yet, for forensic purposes) any rogue accounts created by the tool.",
    "Isolate the endpoint where the command was executed; if the tool was run successfully, the attacker already has SYSTEM-level access to that machine.",
    "Audit all Active Directory and Local Administrator groups across the network to ensure no other unauthorized accounts have been created.",
    "Conduct a full root-cause analysis to determine how the attacker gained the initial administrative privileges required to run the Adduser tool."
  ],
  "what_to_avoid": [
    "Do not assume that deleting the rogue account removes the attacker; if they have `SYSTEM` access, they likely have deployed other backdoors (like scheduled tasks or web shells).",
    "Avoid ignoring alerts for `net.exe /add`; while sometimes used by legitimate IT scripts, it is one of the most common techniques used by ransomware operators and APTs to maintain access."
  ],
  "target_industries": [
    "Global / Opportunistic"
  ],
  "motivation": "Opportunistic",
  "threat_actors": [
    "Unknown / Cybercriminal"
  ],
  "target_geographies": [
    "Global"
  ],
  "attack_stage": [
    "persistence",
    "command_and_control",
    "remote_access"
  ],
  "ecosystem": [
    "windows_pe"
  ],
  "is_emerging": false,
  "sources": [
    {
      "name": "Microsoft Defender Threat Encyclopedia - Backdoor:Win32/Adduser",
      "url": "https://www.microsoft.com/en-us/wdsi/threats/malware-encyclopedia-description?Name=Backdoor:Win32/Adduser"
    },
    {
      "name": "Kaspersky Threat Intelligence - Backdoor.Win32.Adduser",
      "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"
  ]
}