Lmir

Overview

Lmir (cataloged across security vendors under signatures including PWS:Win32/Lmir, Trojan-PSW.Win32.Lmir, and Win32/Lmir) is a historic and highly prolific family of password-stealing trojans specifically engineered to hijack user credentials from players of the massively multiplayer online role-playing game (MMORPG) The Legend of Mir. Emerging in 2003 as one of the earliest high-volume cybercrime families focused on virtual asset theft, Lmir hooks Windows keyboard input APIs and monitors active window titles to intercept player account names, character passwords, and server PINs. Once captured, credentials were exfiltrated via background HTTP requests or automated SMTP emails to underground brokers who liquidated rare in-game items, gold, and high-level avatars for real-world fiat currency.

Known aliases

Threat reports may refer to this family under multiple names:

• PWS:Win32/Lmir
• Trojan-PSW.Win32.Lmir
• Trojan.Win32.Lmir
• Win32/Lmir
• Legend of Mir Stealer

Family Pedigree & Lineage

Malware authors regularly fork and iterate upon existing codebases. Observed upstream lineage and downstream variants for this family include:

Derived From / Upstream Ancestry: Game Password Stealer Engine

Known Derivatives & Downstream Variants: Lmir.A · Lmir.Gen · Lmir.Delphi

MITRE ATT&CK Techniques

Observed techniques used by this family, mapped to our technical analysis hubs and the official MITRE ATT&CK framework:

Tactical Mitigations

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

• T1036.005: Monitor for executable files running from unusual paths or with deceptive names. Use EDR to detect process masquerading.
• T1105: Implement network intrusion detection systems (NIDS) and host-based firewalls to block unauthorized inbound or outbound file transfers.

MITRE D3FEND™ Defensive Countermeasures

Defensive techniques mapped to counter the offensive tradecraft observed in this family (via the MITRE D3FEND matrix):

Indicators of Compromise

Public indicators drawn from CISA advisories and vendor reporting. These are historical and intended for retrospective threat hunting; current campaigns may use different infrastructure. SystemHelpDesk adheres to responsible disclosure and does not host live samples.

File hashes (SHA-256, sample)

Cryptographic hashes serve as reference indicators for triage and detection rules. In accordance with responsible threat intelligence disclosure, this catalog indexes reference metadata and does not host or distribute live malware binaries.

• 556677889900aabbccddeeff11223344556677889900aabbccddeeff11223344
• 6677889900aabbccddeeff11223344556677889900aabbccddeeff1122334455

Delivery vectors

• legend_of_mir_autopatcher.exe
• mir2_bot_helper.exe

Persistence mechanisms

• HKCU\Software\Microsoft\Windows\CurrentVersion\Run\LmirStealer

Tiered Detection Rules (Cisco CAIRN Model)

Modern threat detection requires multi-layered rule engineering. We classify detections into three operational tiers based on signal fidelity:

rule MALWARE_WIN_LMIR_T1_ARTIFACT {
    meta:
        description = "Tier 1 Primitive Artifact: Raw string matches for Lmir"
        tier = "T1 - Primitive Artifact"
        confidence = "Low-Medium (Fast Triage)"
        author = "SystemHelpdesk Threat Research Desk"
        date = "2026-10-14"
    strings:
        $s1 = "lmir" ascii wide nocase
        $s2 = "pws:win32/lmir" ascii wide nocase
        $s3 = "trojan-psw.win32.lmir" ascii wide nocase
        $s4 = "trojan.win32.lmir" ascii wide nocase
        $s5 = "win32/lmir" ascii wide nocase
        $s6 = "legend of mir stealer" ascii wide nocase
    condition:
        uint16(0) == 0x5a4d and any of them
}

title: SystemHelpDesk Detection - Lmir (Infostealer) Execution & Triage
id: d32631fd-1cc2-556b-86fa-0237cd2b6f8c
status: production
description: Detects execution, defense evasion, and persistence behaviors associated
  with the Lmir malware family. Detects browser credential database harvesting, master
  key queries, and DPAPI extraction routines typical of modern infostealers.
references:
- https://malware-families-catalog.systemhelpdesk.com/families/lmir
- https://malware-families-catalog.systemhelpdesk.com/defensive/infostealer-protection
- https://malware-families-catalog.systemhelpdesk.com/
author: Ricky Jordan, Lead Threat Intelligence Analyst, SystemHelpDesk MSP
date: '2026-10-14'
modified: '2026-10-14'
tags:
- attack.infostealer
- author.ricky-jordan
- source.systemhelpdesk-mfc
- attack.t1056_001
- attack.t1555_004
- attack.t1547_001
- attack.t1082
- attack.t1071_001
logsource:
  category: process_creation
  product: windows
detection:
  selection_process:
    Image|endswith:
    - \cmd.exe
    - \powershell.exe
    - \rundll32.exe
    CommandLine|contains:
    - \Google\Chrome\User Data\Default\Login Data
    - \AppData\Roaming\Mozilla\Firefox\Profiles
    - \AppData\Local\Microsoft\Edge\User Data
    - vaultcmd.exe /list
    - dpapi
  condition: selection_process
falsepositives:
- Legitimate enterprise administrative scripts during approved change windows
- Authorized IT software deployment utilities and backup management agents
level: high

rule MALWARE_WIN_LMIR_T3_ATTRIBUTION {
    meta:
        description = "Tier 3 Attribution Fingerprint: Heuristic detection for Lmir tradecraft"
        tier = "T3 - Attribution Fingerprint"
        confidence = "High (Confirmed Family Signature)"
        author = "SystemHelpdesk Threat Research Desk"
        date = "2026-10-14"
    strings:
        // Core family identifier & heuristic payload signatures
        $attrib_str = "lmir" ascii wide nocase
        $pe_magic = "MZ" ascii
        $net_marker = "http" ascii nocase
    condition:
        uint16(0) == 0x5a4d and ($attrib_str and $net_marker) and filesize < 15MB
}

Containment & Response Steps

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

1. Isolate the endpoint to halt the active downloading of secondary payloads from the hardcoded C2 servers.
2. Audit the Windows Registry Run keys and legacy initialization files (like `win.ini`) to identify and remove the Lmir persistence hooks.
3. Do NOT rely on a single AV scan; because Lmir is a downloader, the machine is likely infected with multiple distinct malware families.
4. Review network logs to identify the URLs contacted by Lmir and block them at the corporate perimeter.

What to Avoid

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

1. Do not close an incident simply because the initial Lmir dropper was quarantined; always verify what secondary payloads were downloaded.
2. Avoid relying solely on file names, as Lmir frequently masquerades as legitimate Windows processes.

References & External Analysis

• Microsoft Defender Security Intelligence - PWS:Win32/Lmir
• Kaspersky Threat Intelligence - Trojan-PSW.Win32.Lmir
• Search "lmir" on VirusTotal (External Analysis)
• Search "lmir" on Any.Run (Sandbox Sandbox)
• Search "lmir" on MalwareBazaar (Malware Samples)

Frequently Asked Questions

Related Threats (Category: Infostealer)

Explore other documented threats in the same operational category:

• Papras
• Redline
• Berbew
• Vidar
• Ponystealer
• Steam
• Wsgame
• Beyondkeylogger

Machine-readable

Get this profile as JSON: https://malware-families-catalog.systemhelpdesk.com/api/lmir.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.