Gootkit

Overview

Trojan:Win32/Gootkit (also tracked under names related to Gootloader) is a highly sophisticated, multi-stage Banking Trojan, Information Stealer, and Initial Access payload. Emerging around 2014, Gootkit is unique among banking trojans because its core malicious logic and banking web-injects are written almost entirely in JavaScript/Node.js, executed via an embedded Node.js interpreter, making static analysis extremely difficult.

Understanding Gootkit
To an infected user, Gootkit is invisible until their online banking session is hijacked. For a threat intelligence analyst, Gootkit is a masterclass in obfuscation and modularity. The developers constantly shift their infection vectors (currently relying heavily on 'Search Engine Optimization (SEO) Poisoning' to deliver malicious ZIP files to users searching for business templates). Once established, Gootkit's embedded Node.js engine allows the attackers to push dynamic, on-the-fly script updates to the malware, completely changing its behavior without deploying a new executable.

Execution and Node.js Mechanics
Modern Gootkit infections often begin with a user downloading a weaponized ZIP file (the 'Gootloader' phase) found via poisoned Google search results (`T1189`). The ZIP contains a heavily obfuscated JavaScript file (`T1027.002`). When executed via WScript, this loader performs extensive anti-analysis checks (checking the registry for VMWare/VirtualBox artifacts) (`T1497.001`). It then reaches out to compromised WordPress sites (`T1105`) to download the massive Gootkit payload. The payload establishes persistence via Scheduled Tasks (`T1053.005`) or Registry Run keys. Crucially, the payload contains a full Node.js runtime. It launches `node.exe` (often renamed or injected into a legitimate process) and feeds it the malicious JavaScript core (`T1059.007`). This Node.js script handles all C2 communications, intercepts browser traffic (Man-in-the-Browser), injects fake banking login fields (`T1056.002`), and exfiltrates stolen credentials.

Indicators of Compromise & Impact
The impact is severe financial fraud and potential deployment of secondary ransomware (like REvil, which Gootloader frequently distributed). Incident responders should monitor EDR for the execution of WScript or CScript launching heavily obfuscated `.js` files from temporary directories. Anomalous network traffic (often encrypted TCP over custom ports) originating from injected processes (like `explorer.exe`) is a strong indicator. Memory dumping is required to extract the running Node.js scripts.

MITRE ATT&CK Techniques

Observed techniques used by this family, mapped to the MITRE ATT&CK framework:

Tactical Mitigations

Based on the techniques used by this family, consider the following defensive strategies:

• T1056.002: Monitor for unauthorized keylogging, screen capturing, or web browser API hooking. Deploy EDR to detect API hooking.
• T1059.007: Restrict execution of scripting languages such as PowerShell, VBScript, or Python to authorized administrators. Enforce Script Block Logging.

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_GOOTKIT {
    meta:
        description = "Detects Gootkit (ransomware)"
        author = "SystemHelpdesk Boilerplate Generator"
        date = "2026-07-06"
    strings:
        $s1 = "gootkit" ascii wide nocase
    condition:
        uint16(0) == 0x5a4d and any of them
}

Sigma Rule

title: Suspicious Gootkit Activity
id: fa60d58a5a081fdb79079a8950865e77
status: experimental
description: Detects generic indicators of the gootkit malware family.
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        Image|endswith:
            - '\cmd.exe'
            - '\powershell.exe'
        CommandLine|contains:
            - "*gootkit*"
    condition: selection
level: medium

Containment & Response Steps

Ordered checklist for responders. Adapt to your environment and engage professional support for active incidents.

1. Instantly isolate the endpoint; an active Gootkit infection means the attacker is likely monitoring banking sessions in real-time or preparing to deploy ransomware.
2. Assume all credentials typed on the machine (corporate passwords, banking logins) are compromised and enforce immediate enterprise-wide password resets.
3. Capture a full forensic memory image (RAM dump) to extract the injected Node.js engine and the JavaScript configuration files dictating its targets.
4. Do not trust the operating system; perform a complete bare-metal wipe and reinstall.

What to Avoid

Common mistakes during response to this family that can destroy evidence, spread the infection, or worsen recovery.

1. Do not assume multi-factor authentication (MFA/SMS) will protect you; Gootkit uses web injects to socially engineer the user into typing the MFA code into a fake prompt.
2. Avoid relying solely on file hashes, as Gootloader generates unique, obfuscated JavaScript droppers for nearly every victim.

References & External Analysis

• Search "gootkit" on VirusTotal (External Analysis)

Frequently Asked Questions

Related Families (Category: ransomware)

Explore other malware families in the same category:

• Microjoin
• Jobaka
• Genericrxgf
• Offerbox
• Virgilio

Machine-readable

Get this profile as JSON: https://jordanricky1604-ship-it.github.io/malware-families-catalog/api/gootkit.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.