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Virus.Win32.LEGMIR.JP

December 24, 2019
 Analysis by: Joshua Paul Ignacio
 ALIASES:

W32/PSW.Lmir.oa (ANTIVIR); Trojan-GameThief.Win32.Lmir (IKARUS)

 PLATFORM:

Windows

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:
 INFORMATION EXPOSURE:

  • Threat Type: Virus

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW


This Virus arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

  TECHNICAL DETAILS

Arrival Details

This Virus arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

Installation

This Virus drops the following copies of itself into the affected system and executes them:

  • %Windows%\YZH.exe
  • {Malware Path}\{Malware Filename}.mm
  • {Malware Path}\{Malware Filename}.tmp

(Note: %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.)

It adds the following processes:

  • %Windows%\YZH.exe /zhj
  • {Malware Path}\{Malware Filename}.mm /zhj
  • {Malware Path}\{Malware Filename}.tmp

(Note: %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.)

Autostart Technique

This Virus adds the following registry entries to enable its automatic execution at every system startup:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
YZH = %Windows%\YZH.exe

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
YZH = %Windows%\YZH.exe

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

15.576.03

FIRST VSAPI PATTERN DATE:

23 Dec 2019

VSAPI OPR PATTERN File:

15.577.00

VSAPI OPR PATTERN Date:

24 Dec 2019

Step 1

Trend Micro Predictive Machine Learning detects and blocks malware at the first sign of its existence, before it executes on your system. When enabled, your Trend Micro product detects this malware under the following machine learning name:

     
    • Troj.Win32.TRX.XXPE50FFF031

Step 2

Before doing any scans, Windows 7, Windows 8, Windows 8.1, and Windows 10 users must disable System Restore to allow full scanning of their computers.

Step 3

Note that not all files, folders, and registry keys and entries are installed on your computer during this malware's/spyware's/grayware's execution. This may be due to incomplete installation or other operating system conditions. If you do not find the same files/folders/registry information, please proceed to the next step.

Step 4

Restart in Safe Mode

[ Learn More ]

Step 5

Delete this registry value

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.

  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • YZH = %Windows%\YZH.exe
  • In HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • YZH = %Windows%\YZH.exe

Step 6

Restart in normal mode and scan your computer with your Trend Micro product for files detected as Virus.Win32.LEGMIR.JP. If the detected files have already been cleaned, deleted, or quarantined by your Trend Micro product, no further step is required. You may opt to simply delete the quarantined files. Please check this Knowledge Base page for more information.


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