{
  "family": "centrumloader",
  "sample_count": 12,
  "category": "ransomware",
  "description": "TrojanDownloader:Win32/Centrumloader is a persistent, stealthy malware downloader specifically designed to breach endpoint defenses, establish a foothold, and securely deliver secondary, high-severity payloads. Often sold as a service on underground forums, it acts as an Initial Access Broker (IAB) tool for deploying ransomware, banking trojans, and botnet agents.<br><br><b>Understanding Centrumloader</b><br>To an end-user, a Centrumloader infection is typically invisible; there are no pop-ups, just a silent execution in the background. For threat intelligence analysts, Centrumloader is a critical staging mechanism. Its primary objective is not to steal data directly, but to securely bypass endpoint defenses, profile the infected machine to ensure it is not a sandbox, and reach out to a Command-and-Control (C2) server to pull down the final, destructive payload purchased by the campaign operator.<br><br><b>Execution and Evasion Strategies</b><br>Centrumloader is commonly distributed via massive malspam campaigns containing weaponized attachments (like ZIP files or Office macros) or through exploit kits (`T1566.001`). Upon execution, it utilizes heavy packing and dynamic API resolution to evade static antivirus signatures (`T1027`). It drops a randomized executable into the `%Temp%` or `%AppData%` directory. It establishes persistence by creating a hidden scheduled task (`T1053.005`) or modifying the Registry Run keys. Centrumloader frequently injects its downloading routine into legitimate system processes (like `explorer.exe` or `svchost.exe`) to mask its outbound network traffic as it connects to the C2 (`T1055`).<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' (e.g., Word spawning PowerShell). Network logs will often reveal Centrumloader reaching out to compromised domains using encrypted HTTPS traffic to fetch the secondary payload (`T1105`). 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": [],
  "faq_count": 0,
  "mitre_attack": [
    "T1027",
    "T1053.005",
    "T1105",
    "T1055",
    "T1566.001"
  ],
  "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": "T1053.005",
      "name": "Scheduled Task/Job: Scheduled Task",
      "tactic": "Persistence"
    },
    {
      "id": "T1566.001",
      "name": "Phishing: Spearphishing Attachment",
      "tactic": "Initial Access"
    },
    {
      "id": "T1027",
      "name": "Obfuscated Files or Information",
      "tactic": "Defense Evasion"
    }
  ],
  "containment_steps": [
    "Isolate the endpoint immediately to prevent Centrumloader from downloading and executing its secondary payloads (e.g., ransomware).",
    "Audit the Windows Task Scheduler and Registry Run keys to identify and remove the Centrumloader persistence mechanisms.",
    "Review firewall and proxy logs to identify the C2 domains Centrumloader attempted to contact, and block them enterprise-wide.",
    "Capture a live memory image (RAM dump) to extract the injected modules and identify what secondary payloads were requested."
  ],
  "what_to_avoid": [
    "Do not close an incident simply because the initial Centrumloader 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"
  ]
}