Jakyllhyde

Overview

Executive Summary

Evasion Tactics and Execution Flow

• The "Jekyll" Phase (Evasion): 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.
• The "Hyde" Phase (Execution): 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.

Security Implications

Defense and Mitigation

• Advanced Behavioral Sandboxing: 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.
• Continuous Endpoint Monitoring (EDR): 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.
• Threat Intelligence Sharing: 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.

Known aliases

Threat reports may refer to this family under multiple names:

• Trojan.JakyllHyde
• Evasive.JakyllHyde
• Win32/JakyllHyde

MITRE ATT&CK Techniques

This family has been observed using the following ATT&CK techniques: T1497.001 T1497.002 T1027

Generated Detections (Boilerplate)

These YARA and Sigma rules are auto-generated based on the family name and aliases. They must be heavily tuned before deployment in a production environment.

YARA Rule

rule MALWARE_WIN_JAKYLLHYDE {
    meta:
        description = "Detects Jakyllhyde (ransomware)"
        author = "SystemHelpdesk Boilerplate Generator"
        date = "2026-07-06"
    strings:
        $s1 = "jakyllhyde" ascii wide nocase
        $s2 = "trojan.jakyllhyde" ascii wide nocase
        $s3 = "evasive.jakyllhyde" ascii wide nocase
        $s4 = "win32/jakyllhyde" ascii wide nocase
    condition:
        uint16(0) == 0x5a4d and any of them
}

Sigma Rule

title: Suspicious Jakyllhyde Activity
id: 6b4e3aeee417cbb3fd9290b539731ba9
status: experimental
description: Detects generic indicators of the jakyllhyde malware family.
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        Image|endswith:
            - '\cmd.exe'
            - '\powershell.exe'
        CommandLine|contains:
            - "*jakyllhyde*"
            - "*trojan.jakyllhyde*"
            - "*evasive.jakyllhyde*"
            - "*win32/jakyllhyde*"
    condition: selection
level: medium

References & External Analysis

• Search "jakyllhyde" on VirusTotal (External Analysis)

Frequently Asked Questions

Related Families (Category: ransomware)

Explore other malware families in the same category:

• Nebuler
• Volt
• Genericrxfq
• Capredeam
• Patpoopy

Machine-readable

Get this profile as JSON: https://jordan123234-malware-families-explorer.static.hf.space/api/jakyllhyde.json

Ecosystem & Interactive Environments

This profile is part of the Malware Families Catalog, a public dataset of 2,899 malware families. The catalog is also published across our ecosystem: Hugging Face, Kaggle, Zenodo, Replit, StackBlitz, CodeSandbox, and CodePen.