{
  "family": "hostseditor",
  "sample_count": 1,
  "category": "trojan",
  "description": "<h3>Executive Summary</h3>\nHostsEditor (often categorized as Riskware, HackTool, or Trojan.Hosts) refers to malicious software or scripts designed specifically to tamper with the Windows `hosts` file (`C:\\Windows\\System32\\drivers\\etc\\hosts`). By maliciously altering this critical system file, attackers can redirect web traffic, block access to security updates, and facilitate highly effective phishing campaigns without needing to compromise DNS servers.\n\n<h3>Technical Exploitation and Capabilities</h3>\nThe Windows `hosts` file acts as a local DNS override. Before a computer queries an external DNS server to resolve a domain name (like `www.google.com`) into an IP address, it first checks the `hosts` file. HostsEditor exploits this localized trust.\n\nTypical malicious modifications include:\n<ul>\n<li><strong>Security Blocking:</strong> The malware adds entries that map the domains of major antivirus vendors (e.g., `update.symantec.com`, `microsoft.com`) to the local loopback address (`127.0.0.1`). This completely prevents the infected system from downloading critical antivirus definition updates or OS patches, leaving the system highly vulnerable.</li>\n<li><strong>Phishing Redirection (Pharming):</strong> HostsEditor maps the domain names of popular banks, social media sites, or corporate portals to the IP address of a malicious server controlled by the attacker. When the user types the legitimate URL, they are silently redirected to a pixel-perfect fake login page designed to harvest their credentials.</li>\n<li><strong>Adware Injection:</strong> Some variants redirect high-traffic domains to affiliate ad networks or servers hosting exploit kits.</li>\n</ul>\n\n<h3>Threat Impact</h3>\nModifying the `hosts` file is a subtle but highly effective attack vector. Because the redirection occurs at the OS level, it bypasses browser-based anti-phishing protections. Users believe they are visiting a legitimate site because the URL bar displays the correct domain name, making credential theft highly probable.\n\n<h3>Incident Response and Remediation</h3>\n<ul>\n<li><strong>File Integrity Monitoring (FIM):</strong> The Windows `hosts` file rarely changes in modern enterprise environments. Deploy FIM solutions to immediately alert security teams to any unauthorized modifications to this file.</li>\n<li><strong>Manual Remediation:</strong> The immediate fix requires administrative privileges. Open the `hosts` file in a text editor (like Notepad) and delete all unauthorized IP-to-domain mappings. A clean, default Windows `hosts` file should only contain commented lines (starting with `#`) and the localhost loopback entry.</li>\n<li><strong>Root Cause Analysis:</strong> While fixing the file is trivial, responders must identify *what* modified it. Conduct a full antivirus scan and EDR review to locate the initial malware payload (the HostsEditor) that performed the modification.</li>\n</ul>",
  "cta": "Published by the SystemHelpdesk team.",
  "aliases": [
    "Trojan.Hosts",
    "Riskware.HostsEditor",
    "HackTool:Win32/HostsMod"
  ],
  "enrichment_level": "insufficient_information",
  "faq": [],
  "faq_count": 0,
  "mitre_attack": [
    "T1562.004",
    "T1112",
    "T1562.001"
  ],
  "cisa_advisory": null,
  "last_updated": "2026-07-01T16:39:01Z",
  "type": "Riskware",
  "target_industries": [
    "Global / Opportunistic"
  ],
  "motivation": "Opportunistic",
  "threat_actors": [
    "Unknown / Cybercriminal"
  ],
  "target_geographies": [
    "Global"
  ]
}