{
  "family": "jakyllhyde",
  "sample_count": 1,
  "category": "ransomware",
  "description": "<h3>Executive Summary</h3>\nJakyllHyde (a portmanteau of Jekyll and Hyde) is a highly evasive, two-faced malware family known for its polymorphic characteristics and split-personality execution flow. It is designed to present a completely benign facade during security analysis while delivering a destructive payload when deployed in a production environment.\n\n<h3>Evasion Tactics and Execution Flow</h3>\nJakyllHyde represents a masterclass in anti-analysis and sandbox evasion. The malware derives its name from its operational methodology:\n<ul>\n<li><strong>The \"Jekyll\" Phase (Evasion):</strong> Upon initial execution, the malware conducts exhaustive environmental checks. It looks for indicators of a virtual machine (VMware, VirtualBox drivers), debugging tools, or specific user activity (e.g., checking if the mouse has moved recently or if there are enough files in the \"Recent\" documents folder). If it suspects it is in a sandbox, it behaves like a harmless, benign application—often doing nothing more than writing a harmless text file or simply terminating cleanly.</li>\n<li><strong>The \"Hyde\" Phase (Execution):</strong> If the environmental checks pass (indicating a real, vulnerable user endpoint), the malware dynamically unpacks its true payload. This payload varies by campaign but is frequently a potent info-stealer or a downloader for ransomware.</li>\n</ul>\nThis split behavior allows JakyllHyde to bypass automated email gateways and static signature-based detection systems with ease.\n\n<h3>Security Implications</h3>\nJakyllHyde is incredibly dangerous because it provides a false sense of security. Security analysts or automated systems may analyze the file, observe the benign \"Jekyll\" behavior, and incorrectly classify the file as safe, allowing it to penetrate the network perimeter.\n\n<h3>Defense and Mitigation</h3>\n<ul>\n<li><strong>Advanced Behavioral Sandboxing:</strong> Utilize \"bare-metal\" sandboxing or next-generation sandboxes designed specifically to mimic real human interaction and obscure virtualization markers to trick the malware into its \"Hyde\" phase.</li>\n<li><strong>Continuous Endpoint Monitoring (EDR):</strong> Because initial static analysis may fail, robust EDR is essential to monitor the ongoing behavior of the process post-execution. EDR can detect the delayed unpacking or sudden malicious API calls that occur when the \"Hyde\" payload finally activates.</li>\n<li><strong>Threat Intelligence Sharing:</strong> Rapidly share Indicators of Compromise (IOCs) related to the unpacked \"Hyde\" payload across the security community, as the initial dropper hash will likely change rapidly due to polymorphism.</li>\n</ul>",
  "cta": "Published by the SystemHelpdesk team.",
  "aliases": [
    "Trojan.JakyllHyde",
    "Evasive.JakyllHyde",
    "Win32/JakyllHyde"
  ],
  "enrichment_level": "insufficient_information",
  "faq": [],
  "faq_count": 0,
  "mitre_attack": [
    "T1497.001",
    "T1497.002",
    "T1027"
  ],
  "cisa_advisory": null,
  "last_updated": "2026-07-01T16:09:08Z",
  "type": "Trojan",
  "target_industries": [
    "Global / Opportunistic"
  ],
  "motivation": "Opportunistic",
  "threat_actors": [
    "Unknown / Cybercriminal"
  ],
  "target_geographies": [
    "Global"
  ]
}