{
  "family": "keydownload",
  "sample_count": 1,
  "category": "ransomware",
  "description": "<h3>Executive Summary</h3>\nKeydownload is a classification for a specific category of Trojan Downloaders. Unlike highly sophisticated backdoors, Keydownload malware serves a single, narrow purpose: to covertly infiltrate a system, bypass perimeter defenses, and securely download and execute a much more dangerous secondary payload (often a keylogger, info-stealer, or ransomware) from an attacker-controlled server.\n\n<h3>Infection Vector and Technical Capabilities</h3>\nKeydownload trojans are frequently distributed via drive-by downloads, exploit kits targeting outdated web browsers, or as disguised \"keygen\" (key generator) utilities bundled with pirated software on P2P networks.\n\nOnce executed, the malware prioritizes stealthy communication:\n<ul>\n<li><strong>Evasion and Anti-Analysis:</strong> The executable is typically heavily packed. It often performs environmental checks (looking for sandboxes or analysis tools like Wireshark) before attempting to communicate with its C2 server.</li>\n<li><strong>Encrypted Payload Retrieval:</strong> To evade Intrusion Detection Systems (IDS), the trojan often downloads the secondary payload over HTTPS or uses custom encryption over non-standard ports. The downloaded file is rarely saved to disk in its final executable form; instead, it is decrypted and injected directly into a legitimate running process (Process Hollowing).</li>\n<li><strong>Self-Termination:</strong> Once the secondary payload is successfully running, the Keydownload trojan will often delete itself from the disk to remove forensic evidence of the initial infection vector.</li>\n</ul>\n\n<h3>Threat Assessment</h3>\nThe detection of a Keydownload trojan is a critical event. It is a precursor to a major incident. If the trojan successfully executes, it guarantees that the endpoint is now infected with a primary, highly destructive threat (like a banking trojan) that must be identified and neutralized.\n\n<h3>Incident Response and Remediation</h3>\n<ul>\n<li><strong>Network Triage:</strong> Immediate isolation of the infected machine is required. Analyze network traffic logs (NetFlow, DNS requests) to identify the domains the downloader contacted; these must be blocked at the perimeter to prevent further infections across the enterprise.</li>\n<li><strong>Hunt for the Payload:</strong> Do not assume the system is clean just because the AV deleted the downloader. Responders must utilize EDR or memory forensics to find the injected process (the actual payload) that the downloader successfully deployed.</li>\n<li><strong>Endpoint Re-imaging:</strong> Because the exact nature of the secondary payload can be difficult to determine, the most secure remediation strategy is a complete bare-metal wipe and re-image of the compromised endpoint.</li>\n</ul>",
  "cta": "Published by the SystemHelpdesk team.",
  "aliases": [
    "Trojan-Downloader.Keydownload",
    "Downloader.Keygen",
    "Win32/Keydownload"
  ],
  "enrichment_level": "insufficient_information",
  "faq": [],
  "faq_count": 0,
  "mitre_attack": [
    "T1105",
    "T1027",
    "T1055"
  ],
  "cisa_advisory": null,
  "last_updated": "2026-07-02T06:39:27Z",
  "type": "Trojan / Downloader",
  "target_industries": [
    "Global / Opportunistic"
  ],
  "motivation": "Opportunistic",
  "threat_actors": [
    "Unknown / Cybercriminal"
  ],
  "target_geographies": [
    "Global"
  ]
}