Smokeloader
Overview
Executive Summary
SmokeLoader (also known as Dofoil) is a highly prolific, modular Trojan downloader that has been active in the cybercriminal underground since at least 2011. It operates primarily as an Initial Access Broker (IAB) tool, designed to silently compromise a host, establish stealthy persistence, and "load" (download and execute) secondary, highly profitable malware payloads, such as enterprise ransomware, banking trojans (like TrickBot), or cryptocurrency miners. It is renowned for its aggressive anti-analysis and defense evasion techniques.Infection Vector and Technical Capabilities
SmokeLoader is predominantly distributed through vast, automated spam campaigns (malspam) containing malicious ZIP attachments, macro-enabled Office documents, or via exploit kits hosted on compromised websites. Upon execution, it exhibits advanced evasion and payload delivery:- PROPagate Injection: SmokeLoader is famous for utilizing the PROPagate (process hollowing/injection) technique, injecting its malicious code into legitimate, built-in Windows processes (like `explorer.exe`) to completely hide its execution from task managers and legacy AV.
- Aggressive Anti-Analysis: The loader actively checks for signs it is running in a sandbox or virtual machine (VMware, VirtualBox). If a sandbox is detected, it terminates itself immediately. It also actively attempts to disable Windows Defender and other EDR sensors.
- Plugin Architecture: Beyond its core downloader function, SmokeLoader can receive plugins from its Command and Control (C2) server. These plugins add specific capabilities, such as credential theft from browsers or executing distributed denial-of-service (DDoS) attacks.
Threat Assessment
A SmokeLoader detection is a critical, "Code Red" incident. Because it is a modular loader, the initial infection is rarely the endgame. If SmokeLoader successfully executes, it is almost certain that a devastating secondary payload (like Ryuk or Conti ransomware) is imminent.Incident Response and Remediation
- Immediate Network Isolation: The endpoint must be severed from the network instantly to prevent SmokeLoader from reaching its C2 server to download the secondary ransomware payload.
- Memory Forensics: Because SmokeLoader injects deeply into `explorer.exe`, standard file scanning is insufficient. Incident responders must utilize memory forensics (e.g., Volatility) to identify and extract the injected payload from active RAM.
- Total Re-imaging: Due to its deep system hooking and rootkit-like persistence, cleaning the machine is unreliable. A complete bare-metal wipe and re-image from a known-good baseline is required.
Known aliases
Threat reports may refer to this family under multiple names:
MITRE ATT&CK Techniques
This family has been observed using the following ATT&CK techniques: T1055.002 T1562.001 T1059
Tactical Mitigations
Based on the techniques used by this family, consider the following defensive strategies:
- T1059: 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_SMOKELOADER {
meta:
description = "Detects Smokeloader (loader)"
author = "SystemHelpdesk Boilerplate Generator"
date = "2026-07-06"
strings:
$s1 = "smokeloader" ascii wide nocase
$s2 = "trojan.smokeloader" ascii wide nocase
$s3 = "downloader.dofoil" ascii wide nocase
$s4 = "win32/smokeloader" ascii wide nocase
condition:
uint16(0) == 0x5a4d and any of them
}Sigma Rule
title: Suspicious Smokeloader Activity
id: 886b44916f8e62d9a9da5f7a8b143fb8
status: experimental
description: Detects generic indicators of the smokeloader malware family.
logsource:
category: process_creation
product: windows
detection:
selection:
Image|endswith:
- '\cmd.exe'
- '\powershell.exe'
CommandLine|contains:
- "*smokeloader*"
- "*trojan.smokeloader*"
- "*downloader.dofoil*"
- "*win32/smokeloader*"
condition: selection
level: mediumReferences & External Analysis
- MITRE ATT&CK: Smoke Loader (S0226)
- Search "smokeloader" on VirusTotal (External Analysis)
Frequently Asked Questions
What is SmokeLoader?
A loader whose main job is downloading and installing other malware; it is also known as Dofoil.
How does SmokeLoader avoid detection?
It employs anti-analysis and evasion techniques to hinder researchers and security tools.
What does SmokeLoader deliver?
A wide range of other malware families, depending on the operator using it.
How is SmokeLoader distributed?
Through phishing, exploit kits, and bundling with other malware.
Where is the authoritative reference?
MITRE ATT&CK's Smoke Loader entry (S0226), linked on this page.
How do I remove the Smokeloader Loader from Windows?
Manual removal of Smokeloader is highly discouraged as it may leave persistence mechanisms intact. We recommend disconnecting the device from the internet and utilizing a professional incident response service or enterprise-grade EDR software to conduct a full forensic sweep.
Is Smokeloader a virus or a Loader?
Smokeloader is classified as a Loader. Unlike traditional viruses that infect files, modern malware like Smokeloader typically operates as a standalone payload designed to compromise systems, steal data, or deploy secondary stage implants.
What are the main symptoms of a Smokeloader infection?
Symptoms of Smokeloader can include unexpected system slowness, unauthorized outbound network traffic to unknown IP addresses, disabled security software, and suspicious background processes running from AppData or Temp directories.
Related Families (Category: loader)
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Protect Your Network Against Loaders
Want to prevent Smokeloader and similar threats from compromising your organization? Read our comprehensive defensive guide: Suspect an Infection? What to do.
Machine-readable
Get this profile as JSON: https://jordan123234-malware-families-explorer.static.hf.space/api/smokeloader.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.