{
  "family": "bzub",
  "sample_count": 4,
  "category": "trojan",
  "description": "Bzub (classified in antivirus detection telemetry under designations including Trojan:Win32/Bzub, Trojan.Win32.Bzub, and Win32/Bzub) 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, Bzub 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/Bzub",
    "Trojan.Win32.Bzub",
    "Win32/Bzub"
  ],
  "enrichment_level": "curated_sourced",
  "faq": [
    {
      "@type": "Question",
      "name": "What is Trojan:Win32/Bzub?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Bzub is a trojan threat designed to infiltrate Windows systems and execute unauthorized operations without user consent."
      }
    },
    {
      "@type": "Question",
      "name": "How does Bzub 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 Bzub 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 Bzub 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 Bzub?",
      "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": "2026-10-16",
  "mitre_attack_detail": [
    {
      "id": "T1185",
      "name": "Browser Session Hijacking (Man-in-the-Browser / Web Injects)",
      "tactic": "Collection"
    },
    {
      "id": "T1055",
      "name": "Process Injection (Injecting into browser processes)",
      "tactic": "Defense Evasion"
    },
    {
      "id": "T1555.003",
      "name": "Credentials from Password Stores: Credentials from Web Browsers",
      "tactic": "Credential Access"
    },
    {
      "id": "T1547.001",
      "name": "Boot or Logon Autostart Execution",
      "tactic": "Persistence"
    }
  ],
  "containment_steps": [
    "Immediately isolate the endpoint from the network to sever the C2 connection and prevent the attacker from initiating fraudulent transactions.",
    "Contact the victim's financial institutions immediately to freeze accounts and alert them to the high probability of a Man-in-the-Browser compromise.",
    "Assume all web credentials stored on or entered into the machine have been stolen, and mandate enterprise-wide password resets.",
    "Perform a complete wipe and reimage of the infected machine; banking trojans deeply hook into the OS and cannot be reliably removed by AV alone."
  ],
  "what_to_avoid": [
    "Do not rely on standard MFA (like SMS codes) to protect accounts if a banking trojan is suspected, as the attacker is actively intercepting those codes via social engineering.",
    "Avoid allowing the user to log into any sensitive accounts from the compromised machine, even after an AV scan claims it is clean."
  ],
  "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/Bzub",
      "url": "https://www.microsoft.com/en-us/wdsi/threats/malware-encyclopedia-description?Name=Trojan:Win32/Bzub"
    },
    {
      "name": "Kaspersky Threat Intelligence - Trojan.Win32.Bzub",
      "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"
  ]
}