{
  "family": "nisloder",
  "sample_count": 103,
  "category": "ransomware",
  "description": "TrojanDownloader:Win32/Nisloder is a stealthy, persistent trojan designed to breach endpoint defenses and act as a staging mechanism for the delivery of secondary, high-severity payloads such as ransomware or banking trojans.<br><br><b>Understanding Nisloder</b><br>To an end-user, a Nisloder infection is entirely invisible until the secondary payload executes. For threat intelligence analysts, Nisloder functions as an 'Initial Access Broker' tool. Its primary objective is not direct data theft, but rather securely bypassing initial endpoint controls, verifying the system is not a security sandbox, and establishing a secure connection to a C2 server to pull down the final, destructive payload.<br><br><b>Execution and Evasion Strategies</b><br>Nisloder is commonly distributed via massive malspam campaigns containing weaponized attachments (like macro-enabled Office documents) or through exploit kits. Upon execution, it utilizes heavy packing and obfuscation to evade static antivirus signatures. It drops a randomized, highly entropic executable into the `%Temp%` or `%AppData%` directory. It establishes persistence by creating a hidden scheduled task or modifying the Registry Run keys. Nisloder frequently injects its downloading routine into legitimate system processes (like `explorer.exe` or `svchost.exe`) to mask its outbound network traffic and evade host-based firewalls.<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 Nisloder reaching out to compromised domains or cloud-hosting providers using encrypted HTTPS traffic. The presence of unexpected, hidden scheduled tasks designed to execute randomly named binaries is a strong IoC. Memory analysis is necessary to extract the injected downloader modules and determine what payloads were requested.",
  "cta": "Published by the SystemHelpdesk team.",
  "aliases": [],
  "enrichment_level": "expert-seo",
  "faq": [],
  "faq_count": 0,
  "mitre_attack": [
    "T1027",
    "T1566.001",
    "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": "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 Nisloder from downloading and executing its secondary payloads (e.g., ransomware).",
    "Audit the Windows Task Scheduler and Registry Run keys to identify and remove the Nisloder persistence mechanisms.",
    "Review firewall and proxy logs to identify the C2 domains Nisloder attempted to contact, and block them enterprise-wide.",
    "Capture a live memory image (RAM dump) to extract the injected Nisloder modules and identify the secondary payloads."
  ],
  "what_to_avoid": [
    "Do not close an incident simply because the initial Nisloder 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"
  ]
}