{
  "family": "wintrim",
  "sample_count": 5,
  "category": "trojan",
  "description": "Trojan:Win32/Wintrim is a persistent, stealthy trojan often functioning as an adware clicker or a backdoor designed to breach endpoint defenses and securely deliver secondary payloads. It is known to heavily inject intrusive advertisements or silently click on hidden ads to generate fraudulent revenue for the attackers.<br><br><b>Understanding Wintrim</b><br>To an end-user, a Wintrim infection is typically noticed through severe system sluggishness, unexpected pop-up windows appearing even when browsers are closed, or redirected web searches. For threat intelligence analysts, Wintrim represents a significant nuisance and a potential staging mechanism for further infections, as adware botnets are frequently rented out to distribute more severe malware.<br><br><b>Execution and Evasion Strategies</b><br>Wintrim is commonly distributed via massive malspam campaigns containing weaponized attachments, software bundles (`T1189`), or through exploit kits. Upon execution, it utilizes packing to evade static antivirus signatures. It drops a randomized executable into the `%Temp%` or `%AppData%` directory. It establishes persistence by creating a hidden scheduled task or modifying the Registry Run keys. Wintrim frequently injects its ad-clicking or downloading routine into legitimate system processes (like `explorer.exe` or `svchost.exe`) (`T1055`) to mask its outbound network traffic and hide its activity from the user.<br><br><b>Indicators of Compromise (IoCs)</b><br>Threat hunters should investigate EDR alerts related to 'Suspicious Process Injection' or 'Anomalous Child Process Spawning'. Network logs will often reveal Wintrim reaching out to known advertising networks or compromised domains using encrypted HTTPS traffic, often generating massive amounts of automated clicks. The presence of unexpected, hidden scheduled tasks designed to execute randomly named binaries in the user's profile is a strong IoC.",
  "cta": "Published by the SystemHelpdesk team.",
  "aliases": [],
  "enrichment_level": "expert-seo",
  "faq": [
    {
      "@type": "Question",
      "name": "What is Wintrim and what threat category does it belong to?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Wintrim is classified as a Trojan. 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 Wintrim establish persistence and evade defensive controls?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Wintrim 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 Wintrim compromise?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Security teams responding to Wintrim 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 secondary payloads and staging behaviors are commonly associated with Wintrim?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Wintrim frequently operates as a loader or dropper designed to establish a foothold before downloading and executing secondary high-impact malware payloads. Depending on the threat actor's objectives, these dropped modules can range from ransomware and banking injects to modular infostealers and remote management backdoors."
      }
    },
    {
      "@type": "Question",
      "name": "How can security operations teams effectively detect and hunt for Wintrim across enterprise endpoints?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Defenders should hunt for Wintrim by deploying behavioral endpoint detection and response (EDR) rules that monitor suspicious process spawning (such as cmd.exe or powershell.exe spawned from office documents or temporary directories), anomalous outbound network connections from non-browser binaries, and unauthorized modifications to Windows Run keys and scheduled task registries."
      }
    }
  ],
  "faq_count": 5,
  "mitre_attack": [
    "T1189",
    "T1027",
    "T1055",
    "T1105",
    "T1547.001"
  ],
  "cisa_advisory": null,
  "last_updated": "2026-06-09",
  "mitre_attack_detail": [
    {
      "id": "T1105",
      "name": "Ingress Tool Transfer",
      "tactic": "Command and Control"
    },
    {
      "id": "T1055",
      "name": "Process Injection",
      "tactic": "Defense Evasion"
    },
    {
      "id": "T1547.001",
      "name": "Boot or Logon Autostart Execution: Registry Run Keys / Startup Folder",
      "tactic": "Persistence"
    },
    {
      "id": "T1189",
      "name": "Drive-by Compromise",
      "tactic": "Initial Access"
    },
    {
      "id": "T1027",
      "name": "Obfuscated Files or Information",
      "tactic": "Defense Evasion"
    }
  ],
  "containment_steps": [
    "Isolate the endpoint immediately to prevent Wintrim from generating ad fraud traffic or downloading secondary payloads.",
    "Audit the Windows Task Scheduler and Registry Run keys to identify and remove the Wintrim persistence mechanisms.",
    "Review firewall and proxy logs to identify the C2 or ad-network domains Wintrim attempted to contact, and block them enterprise-wide.",
    "Run a comprehensive anti-malware and adware removal scan to ensure all injected components are removed from the system."
  ],
  "what_to_avoid": [
    "Do not close an incident simply because the initial Wintrim dropper was quarantined; always verify if secondary payloads were downloaded.",
    "Avoid relying solely on manual file deletion, as the injected processes will likely just recreate the dropped binaries."
  ],
  "target_industries": [
    "Global / Opportunistic"
  ],
  "motivation": "Opportunistic",
  "threat_actors": [
    "Unknown / Cybercriminal"
  ],
  "target_geographies": [
    "Global"
  ],
  "attack_stage": [
    "execution",
    "persistence"
  ],
  "ecosystem": [
    "windows_pe"
  ],
  "is_emerging": false,
  "target_platforms": [
    "Windows 11",
    "Windows 10",
    "Windows 7"
  ]
}