Lemoore
Overview
Executive Summary
Lemoore is a malicious Trojan designed to covertly infiltrate Windows systems, establish persistence, and act as a reliable downloader for remote threat actors. It is frequently utilized in the initial stages of a cyberattack to gather system intelligence and facilitate the automated deployment of secondary, highly destructive malware payloads, such as banking trojans or ransomware.Infection Vector and Technical Capabilities
Lemoore is predominantly distributed through socially engineered spam campaigns containing malicious attachments (often weaponized PDFs or Microsoft Office documents) or via compromised software installers downloaded from untrustworthy web portals. Upon successful execution, Lemoore operates with a focus on stealth and payload delivery:- System Reconnaissance: The trojan immediately collects detailed system information, including the OS version, installed software, network configuration, and active antivirus solutions. This fingerprint is transmitted to a command-and-control (C2) server.
- Persistence: Lemoore ensures it survives system reboots by modifying the Windows Registry (e.g., adding entries to the `Run` key) or by dropping a shortcut into the Windows Startup folder.
- Payload Delivery: Acting as a downloader, Lemoore receives instructions from the C2 server to download and execute secondary malware. This frequently includes info-stealers (to harvest credentials) or botnet agents.
Threat Assessment
A Lemoore infection represents a significant breach of the endpoint perimeter. Because it provides remote attackers with the ability to execute arbitrary code, a compromised machine can quickly be utilized to pivot laterally across the corporate network.Remediation and Eradication
- Endpoint Detection and Response (EDR): Configure EDR solutions to monitor for anomalous registry modifications and unauthorized outbound network connections to unknown IP addresses.
- Network Isolation and Sweeps: Immediately isolate the infected endpoint. Conduct a thorough forensic sweep to identify not only the Lemoore executable but also any secondary payloads it may have successfully downloaded.
- Credential Reset: Because Lemoore often facilitates the deployment of info-stealers, all user credentials associated with the compromised endpoint should be treated as compromised and immediately reset.
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: T1105 T1547.001 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.
- T1105: Implement network intrusion detection systems (NIDS) and host-based firewalls to block unauthorized inbound or outbound file transfers.
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_LEMOORE {
meta:
description = "Detects Lemoore (ransomware)"
author = "SystemHelpdesk Boilerplate Generator"
date = "2026-07-06"
strings:
$s1 = "lemoore" ascii wide nocase
$s2 = "trojan.lemoore" ascii wide nocase
$s3 = "downloader.lemoore" ascii wide nocase
$s4 = "win32/lemoore" ascii wide nocase
condition:
uint16(0) == 0x5a4d and any of them
}Sigma Rule
title: Suspicious Lemoore Activity
id: 118a778f6340c4d80dc3656323cbd4da
status: experimental
description: Detects generic indicators of the lemoore malware family.
logsource:
category: process_creation
product: windows
detection:
selection:
Image|endswith:
- '\cmd.exe'
- '\powershell.exe'
CommandLine|contains:
- "*lemoore*"
- "*trojan.lemoore*"
- "*downloader.lemoore*"
- "*win32/lemoore*"
condition: selection
level: mediumReferences & External Analysis
- Search "lemoore" on VirusTotal (External Analysis)
Frequently Asked Questions
How do I remove the Lemoore Ransomware from Windows?
Manual removal of Lemoore 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 Lemoore a virus or a Ransomware?
Lemoore is classified as a Ransomware. Unlike traditional viruses that infect files, modern malware like Lemoore typically operates as a standalone payload designed to compromise systems, steal data, or deploy secondary stage implants.
What are the main symptoms of a Lemoore infection?
Symptoms of Lemoore 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: ransomware)
Explore other malware families in the same category:
Protect Your Network Against Ransomwares
Want to prevent Lemoore and similar threats from compromising your organization? Read our comprehensive defensive guide: Ransomware Protection Guide.
Machine-readable
Get this profile as JSON: https://jordanricky1604-ship-it.github.io/malware-families-catalog/api/lemoore.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.