{
  "family": "nlbrute",
  "sample_count": 1,
  "category": "ransomware",
  "description": "<h3>Executive Summary</h3>\nNLBrute is a notorious, commercially available hacking tool specifically designed to perform high-speed, automated brute-force attacks against the Remote Desktop Protocol (RDP - Port 3389). It is widely utilized by initial access brokers and ransomware syndicates to compromise internet-facing Windows servers, establishing a persistent foothold within corporate networks.\n\n<h3>Technical Architecture and Operational Tactics</h3>\nNLBrute is highly efficient, capable of attempting thousands of credential combinations per minute. Its operational flow involves:\n<ul>\n<li><strong>Target Acquisition:</strong> Attackers first utilize internet-wide scanning tools (like Masscan or ZMap) to identify servers with Port 3389 open to the public internet.</li>\n<li><strong>Brute-Forcing:</strong> NLBrute is then deployed against the identified targets, utilizing massive, curated dictionaries containing common usernames (Administrator, Admin) and millions of compromised passwords.</li>\n<li><strong>Evasion:</strong> The tool often supports the use of proxy lists (SOCKS4/5) to distribute the attack traffic across hundreds of IP addresses, making it difficult for basic rate-limiting or IP blocklists to thwart the attack.</li>\n</ul>\nOnce NLBrute successfully guesses a valid credential pair, the attacker gains full, interactive GUI access to the compromised server, bypassing all perimeter defenses.\n\n<h3>Threat Impact</h3>\nAn NLBrute compromise is a catastrophic security failure. By gaining RDP access, the attacker operates with the privileges of the compromised user (often a domain administrator). This allows them to seamlessly disable security software, deploy ransomware (like Dharma or Phobos), and exfiltrate sensitive corporate data without triggering malware alerts.\n\n<h3>Defense and Resilience Strategies</h3>\n<ul>\n<li><strong>RDP Hardening:</strong> Never expose RDP (Port 3389) directly to the public internet. Require users to connect via a secure Virtual Private Network (VPN) or a Remote Desktop Gateway before accessing internal RDP servers.</li>\n<li><strong>Multi-Factor Authentication (MFA):</strong> Enforce strict MFA for all RDP connections. Even if NLBrute successfully guesses the password, the attack will fail without the secondary authentication token.</li>\n<li><strong>Account Lockout Policies:</strong> Implement stringent account lockout policies (e.g., locking an account after 5 failed login attempts) to mathematically defeat brute-force methodologies.</li>\n</ul>",
  "cta": "Published by the SystemHelpdesk team.",
  "aliases": [
    "HackTool.NLBrute",
    "RDP.BruteForcer",
    "Win32/NLBrute"
  ],
  "enrichment_level": "insufficient_information",
  "faq": [],
  "faq_count": 0,
  "mitre_attack": [
    "T1110.001",
    "T1133",
    "T1078.002"
  ],
  "cisa_advisory": null,
  "last_updated": "2026-07-01T16:13:06Z",
  "type": "HackTool",
  "target_industries": [
    "Global / Opportunistic"
  ],
  "motivation": "Opportunistic",
  "threat_actors": [
    "Unknown / Cybercriminal"
  ],
  "target_geographies": [
    "Global"
  ]
}